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Wilitrun
David M

(45 posts)

Registered:
10/21/2021 05:17PM

Main British Car:


300 Stroker questions?
Posted by: Wilitrun
Date: January 18, 2022 11:04AM

Hello all,
Starting to plan out my 300 build, and have had a few public and private conversations with Jim B. that have been extremely valuable. Rather than continue to monopolize his time, I thought I'd ask some public questions.
Background: This is a '64 300 with aluminum heads and originally 2bbl intake, I have a 4bbl intake to use but not the 4V compression ratio. The engine is worn-out and needs complete overhaul, a lot of the internals are junk including the cam and quite possibly the front cover (oil pump) as the engine was on a run-to-fail program before the car was cashed-in. So assuming the block passes inspection, I'm a bit flexible on rotating assembly components. I consider dynamic balancing a must. Oiling system improvements, as have been well-documented, and explained to me carefully by Jim, also are a must. I'm installing it in a '78 B roadster with a V6 T5 and H-body bell. Rear axle has not yet been sourced but will likely be a D44 LSD between 3 and 3.4 RP.
I have been looking into the extra cost of components to use the late 350 crank, and I don't hate it.
I'm also confident in the ability of my local machinist, so I'd like to look into just the rotating assembly swap.
I've spent a lot of time searching, and can't find any breakdown on the evolution of the 350 crank, so I'm wondering what year spread and identifiers I should be looking for when shopping for a good 350 crank to use. Jim had mentioned the "late" version had enough counterweight to minimize the need for mallory metal when balancing, if the rods and pistons are light enough.
Improving the rod ratio to reduce side-loads, and ease of internal balancing when using the Nascar 6.2 take-off rods appeals greatly to me. Also the ability to dial in deck height by ordering a piston, as I'd like to set it so high-octane pump gas can still be used (I'd prefer something on the order of 9.7:1). I realize breathing improvements would be needed to maximize horsepower, but that's not my goal. I'd like to reduce stresses on the engine at the power levels I want to be using. I don't see the percentage in going so far as the TA heads for me, at least until I get used to the engine with stock ones (or perhaps slightly bigger valves), but I suppose it would be nice to have the bottom-end ready to take advantage if I did decide to upgrade later. But again, low to midrange rpm is 90% of where I'll be and I would like to drive the car quite often.
I hadn't thought of insisting on thoroughly vetting the block before starting machine work, Chris Gill's journal made that clear (while also providing a lot of inspiration and appreciation of his attention to detail!).
As an aside, a mild roller cam may increase my costs substantially at the beginning but the investment seems to be good economy to increase longevity of the valvetrain. I doubt many are asking how to make the most of a mild profile but if there's a resource someone can point me to, or if you think just a roller version of the stock profile is a good choice, I'd appreciate the feedback. Cheers.


mgb260
Jim Nichols
Sequim,WA
(2277 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: 300 Stroker questions?
Posted by: mgb260
Date: January 18, 2022 11:34AM

David, I have a little experience with what you plan to do. The late crank has capscrew rods. 74-80. The roller cam that Jim B is doing would be perfect. Specs are GM LT1 "Hot" cam. You can go to 10.5 compression with the aluminum heads, The stock intake is not the best, but the only one available at this time. Brian Mcmillan is working with Anthony Laney in Australia on a great intake for the 300. I used larger 2.3 Ford sohc 1.74 intake and 1.5 exhaust valves in my 300 heads years ago. You will need larger valve seats. Chevy Z28 springs and Viton seals after guides were machined down and bronze liners installed. Are you going to use a carb or Fuel injection? I prefer Quick Fuel HR series or Holley Sniper. Any question you have I'll be glad to help.


Wilitrun
David M

(45 posts)

Registered:
10/21/2021 05:17PM

Main British Car:


Re: 300 Stroker questions?
Posted by: Wilitrun
Date: January 18, 2022 12:11PM

Thank you Jim, and again, thanks for your generous help in past questions.
I've been following the Willpower Intake developments, but took up Glenn T on his generous offer of an original 4bbl aluminum intake. Indeed I prefer a carburetor for a number of reasons, so would prefer to go with that. Pump gas again is my preference. I've been reading input from both of you on the V8Buick sticky, but unfortunately do not have posting privileges there as yet. I do appreciate all the generous information being shared as it's clearly a niche engine with a lot of potential. Cheers.


mgb260
Jim Nichols
Sequim,WA
(2277 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: 300 Stroker questions?
Posted by: mgb260
Date: January 18, 2022 12:20PM

David, 10.5 on an aluminum head is octane tolerant as 9.5 on an iron head. The cam Jim B is using is a hydraulic cam. Corvette 350 cam specs. He is using solid lifters with it. The Dynamic compression with that cam would allow premium pump gas.



Edited 1 time(s). Last edit at 01/18/2022 12:21PM by mgb260.


mgb260
Jim Nichols
Sequim,WA
(2277 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: 300 Stroker questions?
Posted by: mgb260
Date: January 18, 2022 02:23PM

Weak spot on the 300 heads are the rocker hold down holes. Steel thread inserts there are a good idea.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6274 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: 300 Stroker questions?
Posted by: BlownMGB-V8
Date: January 18, 2022 02:43PM

On the heads, you must pay attention to chamber volume as it affects your piston dish size. The 300 heads have about a 35cc dish which is quite large, the TA heads have about a 26cc dish which is much smaller. So the short block has to be built for the heads you will use. Now one rather clever dodge is to find a set of late Rover heads which are nearly as good as the aluminum 300 heads, build for those and the TA heads will then work as the stock Rover heads have the small chamber. That gives you the flexibility for a later upgrade without having to spend too much to do it. I'm using Wiseco slipper style pistons and got a good price on them, something like $1140 a set. You can have them reference mine if you like, they were sold to DAM in Culloden, WV. Shouldn't be hard to find. They are spec'd for the TA heads and a 10.5 CR and purchased within probably the last year and a half.

Cams: I actually have 2 roller cams coming in, one is a hydraulic grind and the other is for the solids. Both the same grind profile as Jim said though one engine will have a rather conventional redline and the other is built for extra speed capability, just because I want it. They are supposed to ship within about a week. Lead times have gone way up, figure on a couple of months or more. I bought those from TA and had them handle getting them ground also. Don't know if they have the cores back in stock yet though. We almost had to cut down a higher lift core and have it re-hardened. That is an option. Not many of these stock or near stock grinds get used for aftermarket roller cams, at least not yet. But we are in a rather specialized niche here as we have the luxury of an oversized engine and can build it mild and still get great performance, which makes for long life. And in street driving it's mostly about torque so a mild grind has some advantages until you start winding it up. The roller doesn't need oil squirters in the rods or extra zinc in the oil and one teardown for a wiped lobe pays for it. If you can get the Pankl rods they are extremely nice and offer more clearance for the block and cam but finding the bearing shells is a little tricky. Watch your crank end play, big end side clearance, and oil slinger clearance. Also rod clearance to the block at the oil suction galley casting and rod clearance to the rear cam lobes. Those will be close but with the Pankl rods should clear. Haven't checked the cam clearance yet but it should be OK.

Jim


mgb260
Jim Nichols
Sequim,WA
(2277 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: 300 Stroker questions?
Posted by: mgb260
Date: January 18, 2022 03:00PM

Jim, One correction, 300 heads are around 55cc not 35cc. Typo?



Wilitrun
David M

(45 posts)

Registered:
10/21/2021 05:17PM

Main British Car:


Re: 300 Stroker questions?
Posted by: Wilitrun
Date: January 18, 2022 04:07PM

Quote:
Jim Blackwood
we have the luxury of an oversized engine and can build it mild and still get great performance, which makes for long life.

Yes, my thinking as well, thank you; though I have not built many engines (this will be my third engine specced in 25 years) and I'm a little rusty on how to get there. But this is my underlying motivation.
I'm assuming head gaskets aren't available in different thicknesses to give me some flexibility. But I'm certainly not opposed to committing to the stock aluminum heads if that's the case. Perhaps if I go conservative with my compression ratio and these heads fail at some point I can put in iron 300 heads later and build them, and deal with the handling issues of the extra weight if need be. Having run rear-drive cars that were heavily front-biased for most of my life and not having done any racing I don't anticipate this being a big problem for me, though I remember Anthony H. talking about the understeer of his 289 powered GT when I met him this fall, and without knowing how he drove it, I do get the value of neutral handling. The iron heads are cheap and at this point not yet too difficult to get, and that's always a hook for me. If I have to replace heads and can solve it with a couple hours on Kijiji and a few weeks at the machine shop - right on.

Quote:
Jim Nichols
Weak spot on the 300 heads are the rocker hold down holes. Steel thread inserts there are a good idea.

Indeed, I saw those when pulling the shafts and remember how odd it seemed to have the bolts threading right into the aluminum if they're service removable and one was heavy coming all the way out so they need reinforcement for sure.

Question: Does anyone recall seeing a picture side-by-side of the late 350 crank next to an early one, or know the number for the late one (if it's cast into the crank somewhere)? I may have someone who can look for me but I can't rely on him to know exactly what to look for and knowing myself would make having him snap a picture for me a lot more practical. I think someone may have mentioned an extra counterweight on the flywheel flange but I have to admit I don't know what I'm looking at here. Locally I've located a '69 and a '71 that sold and neither had the rods to go with them, oddly no shortage of Olds 350s here but no late Buicks without the car yet, my friend is in the Edmonton area where there's a lot more supply. At least with 74-80 we now at least know where to look, so thanks again for that. Ironic that there's a gold nugget hidden in an undervalued malaise-era car and we can do something for little outlay that ought to cost much more, that's what's really tugging me to do this while I have everything apart and can take advantage. Cheers.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6274 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: 300 Stroker questions?
Posted by: BlownMGB-V8
Date: January 18, 2022 04:18PM

Thanks Jim, I do slip up occasionally, like anyone else.

For a mostly stock engine I do believe the late 350 rotating assembly could make a usable choice. The rod length is 6.387" which would make the ring package a tight fit. The deck on the 300 is .644" shorter than the 350 which means you have to find 5/8" between the lower ring and the top of the wrist pin and with the stock .939" diameter pin that's going to be really tight. But, the late capscrew rods are pretty good and fine for up to about a 6K redline, maybe a bit more. They should fit in the block fine and cam clearance will be exactly the same as in the 350. They use the stock bearing inserts and have oil squirter holes for cam lobe and cylinder lubrication. So as to the fit, with forged pistons the ring package can be moved up a bit especially if power adders aren't used. It's acceptable to go with thinner rings, and the rods can be bushed to allow the use of smaller diameter wrist pins, all of which should give more than enough room.

For example, in my 340 I used 7" rods with 3/4" pins and a fairly standard ring package on pistons designed for a blower engine. Distance between the pin and ring was not a lot, going from memory it seemed like around 3/16" at the most but let's run the numbers. A 7" rod vs 6.387" gives .613" so that leaves .031" to make up and there would have been room to do that. But, a 3/4" wrist pin while compact and light in weight, is not probably quite as durable as could be desired. A whole book could be written just about wrist pins but taking the piston manufacturer's recommendation is usually a safe approach. However, if bushing the stock rods is considered, a diameter in the low 8's should give adequate bushing wall thickness and this gives room with the same ring package I used on the 340. Hardened alloy thin wall wrist pins can give a weight of around 100 grams, less than half of stock. Now, this doesn't help much with the balancing as the stock rods are heavy so an internal balance might not be practical even with light pins and slipper style pistons, which shifts expenses from the internals to the flywheel etc, but it's still possible, and may be a good practical choice.

Jim


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6274 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: 300 Stroker questions?
Posted by: BlownMGB-V8
Date: January 18, 2022 04:40PM

As to the iron heads, yes they do have bigger ports and valves and yes they are a bit heavier. Interestingly enough there isn't but a few lbs difference in weight between an iron head and a TA head. But the flow is considerably different. Weight difference between the stock alloy head and iron head 300 is 50 lbs divided between 2 heads and the intake just about evenly. So with the alloy intake it's only about 35lbs. and that much isn't going to kill the handling. Doesn't help but it can be pretty much tuned out. The late Rover heads are also a bit heavier than the 300 heads. So there are two very practical ways to go on the heads. Either the Rover with TA as an upgrade or the stock 300 alloy/iron combo. Either one works but the first has more power potential as you would expect.

Jim


mgb260
Jim Nichols
Sequim,WA
(2277 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: 300 Stroker questions?
Posted by: mgb260
Date: January 18, 2022 04:46PM

On Chris's build the capscrew rods were lightened quite a bit by removing most of the balancing pads top and bottom. The 2.5 Sohc Ford Speed-Pro hyper pistons were a lot lighter and used modern thin rings. 1.19 compression height with small dish and valve reiefs gave about 10.2 compression. Those pistons standard size is 3.78 so .020 is 350, 3.8 standard size. Only clearance issue with the longer 350 rods was the shallow part of the oil pan need a little ball peen work and washers under the windage tray. Biggest expense was turning the crank down .5" on the mains. Also, the oiling hole has to be chamfered over to center and oil seal crosshatch polished for rubber seal. Ian, the owner of the car just told me it was running better than ever since he has had some Megasquirt tuning done. The iron heads have much bigger ports and valves than the 300 aluminum heads. You wouldn't notice the extra weight.



Edited 3 time(s). Last edit at 01/18/2022 05:10PM by mgb260.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6274 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: 300 Stroker questions?
Posted by: BlownMGB-V8
Date: January 18, 2022 04:54PM

If you can look at the rods, the late cranks use the capscrew style rod bolts as opposed to the through-bolt and nut style so that makes an easy identifier.

Jim


Wilitrun
David M

(45 posts)

Registered:
10/21/2021 05:17PM

Main British Car:


Re: 300 Stroker questions?
Posted by: Wilitrun
Date: January 18, 2022 05:25PM

"Full Throttle Enterprises" on eBay has a set of Pankl 6.2 Nascar take-offs for $85.00USD, so unless the bearings are extremely difficult to get or expensive I see no reason not to go with them (or say a slightly different height if we are playing with length to stay out of the ring pack/fine-tune deck height.
Very glad to hear the feedback about the iron heads. Certainly it seems worth it to me to find an extra set to play with.
I'll keep looking for a motor, that seems the only way to verify the rod type if I can't pick out the crank differences easily (which is good to know). No engines showing on car-part at the moment, but that usually doesn't include the u-pull sections so maybe that's not an issue. Cheers.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6274 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: 300 Stroker questions?
Posted by: BlownMGB-V8
Date: January 18, 2022 06:08PM

When you buy them get them to give you the order information for the shells and you should be good. Expect to spend more on the inserts than you do on the rods, maybe as much as 50% more and there may be only one size and one type available, the same one that is used in the racing engines. Which shouldn't be a problem assuming clean assembly of the engine. But the rods themselves are super nice. Wouldn't surprise me a bit if the MSRP is around 2 grand a set. I really like those rods.

Jim


Wilitrun
David M

(45 posts)

Registered:
10/21/2021 05:17PM

Main British Car:


Re: 300 Stroker questions?
Posted by: Wilitrun
Date: January 18, 2022 06:31PM

Quote:
Jim Blackwood
there may be only one size and one type available, the same one that is used in the racing engines.

Good point, I hadn't thought of that. Would the 6.2 Honda rods spoken about early in the v8buick sticky be a better option if I had some bottom-end problem and had to clean up the rod journals again? Or have they been looked at with the 350 crank in a 300 and maybe I just have to blaze a new trail. Cheers.



BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6274 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: 300 Stroker questions?
Posted by: BlownMGB-V8
Date: January 18, 2022 06:42PM

You won't know for sure until you ask. All I can tell you is that of the last 2 sets of rods I've bought one did and one didn't.. So the best thing is to ask.

Jim


Wilitrun
David M

(45 posts)

Registered:
10/21/2021 05:17PM

Main British Car:


Re: 300 Stroker questions?
Posted by: Wilitrun
Date: January 18, 2022 09:33PM

It's possible I either poorly phrased my question, or "Honda rods" doesn't mean what I think it does. But I'm not proud, so I'll ask:
So when I hear there's only one size of service bearing (or there might be) for the Pankl rod (which would make sense on a stock car), I immediately think I have no recourse if I've sized my crank for it and have to clean it up later for any reason. So I think it might be better for me to use a production engine rod of the same length I want, like the 6.2 Honda rod, (does that reference the manufacturer, or just the big/small end dimensions on a race rod?) and if I spin a bearing on a rod I have some option to clean it up and throw it back together with a service undersize bearing. Of course, that assumes that a production Honda rod will still clear everything or be light enough to dynamically balance internally, which I'd prefer. Since I'm using a stick, I'd like to replace the flywheel without too much consequence if something should happen to the clutch. From how you've phrased your response I may have inadvertently stepped into another race rod of another size, which wouldn't solve this potential problem. Cheers.


BlownMGB-V8
Jim Blackwood
9406 Gunpowder Rd., Florence, KY 41042
(6274 posts)

Registered:
10/23/2007 12:59PM

Main British Car:
1971 MGB Blown,Injected,Intercooled Buick 340/AA80E/JagIRS

authors avatar
Re: 300 Stroker questions?
Posted by: BlownMGB-V8
Date: January 19, 2022 12:07PM

David, I don't know any of the details about the stock Honda rod. Both the Pankl and Carillo rods I now have use a Japanese bearing size. I can't say for sure which one showed one insert available since Dustin chased down the bearings but I Think it was the Pankl. The rods had a serial number and he used that to match up the insert. Maybe you could use a different insert to match up for an undersized bearing, or resize the rod to do that, it seems likely to me but I have no way of telling you that for certain any more than I can say for certain that it was the Pankl rods or the Carillo. What I can say is that the Pankl rods were an easier fit in the block so I'd use them if I could. They also have that nice 3 dimensional mating surface where the cap mates, and it goes together like a finely machined watch. Between the seller and your shop I think the insert situation could be sorted out. Certainly can't beat the price. I've also used Scat rods and those needed one shoulder clearanced for the cam but they also used the Buick bearing shell. Of course the stock rods also work fine for more reasonable redlines but they are cast steel.

Jim


Wilitrun
David M

(45 posts)

Registered:
10/21/2021 05:17PM

Main British Car:


Re: 300 Stroker questions?
Posted by: Wilitrun
Date: January 19, 2022 05:21PM

Thanks Jim for this, it appears I did mistake the "Honda" rod term to mean a production engine rod from a Honda rather than a race rod with Honda bearing dimensions. All clear now.
I think I have enough information to start tracking down parts. Cheers.


mgb260
Jim Nichols
Sequim,WA
(2277 posts)

Registered:
02/29/2008 08:29PM

Main British Car:
1973 MGB roadster 260 Ford V8

Re: 300 Stroker questions?
Posted by: mgb260
Date: January 19, 2022 06:08PM

Chris's build is going on 8 years now! Another alternative is using 3800 Buick V6 supercharged pistons with the capscrew rods and 64 Aluminum or Iron heads. About 9.75 compression. Those pistons use bushed rod and smaller floating pins with circlip. 3.8 standard, so .050 over on the 300. Hyper with coated skirts and anodized crown. You would have to talk them into selling you two more piston and ring sets.

[www.ebay.com]



Edited 3 time(s). Last edit at 01/21/2022 01:00AM by mgb260.
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