Engine and Transmission Tech

Bryan, What is intake centerline installed at ? IMHO, this sounds a bit much, on the exhaust side, for a blown application. It's likely your cam and carburetion needs will change with the bigger blower, increased head flow, and more boost. I prefer using the bottom row of head "studs", as this is the weaker side of the head,(exhaust temp vs. aluminum). I would consider bolting the blower manifold to the China Wall, front and rear, to better stabilize the top end. This appears to be primarily, a drag car ? RPM drop, when it shifts ? Automatic ? Switching to a roller ? This build would "like" E85 ! Good Luck, roverman.



Edited 1 time(s). Last edit at 03/17/2013 03:55PM by roverman.

Interesting. That's a significantly bigger cam that I'm using in my 340 but I'll probably be running higher manifold pressure. My specs are 212@.050" (262 adv.), .436" lift and 112 lobe separation. However, this cam is also noticeably bigger than the stock cam I used with the 215. It's a custom grind designed to give a wide torque curve and allow boost to extend the redline to 7000 rpm, without necessarily increasing output above 6 grand, while allowing spring pressures in the neighborhood of 110/260, which also allowed me to reuse my old Comp Cams single springs from the HiPo Buick 215 I originally had in the car. Also I am not shooting for a horsepower number much over 300 and prefer to keep the torque up, the static compression high, and optimize for economy. I figure the less gas it burns the more I can drive it.

From my 4 wheeling days, I was very pleased with the CC 268H cam in my old International Travelall 392 and liked the Schneider cam even better, but it did not have a blower. I'm not sure how that would have turned out with that cam.

I don't know if any of this helps but if it adds any perspective I guess that's good for something.

Jim

Thank you for sharing your wealth of knowledge with me,
Just found some more paperwork,when the engine was dyno'd,I had two pulleys with me,originally it was under driven,and the dyno result I posted up,was 1 - 1
Being a little disappointed,I took the blower and manifold to a reputable blower builder,my aim was to part exchange it,for a 6:71 !
I was talked out of it ! They checked my blower out,made me a new pulley (10% over) and built me a new inlet manifold.I haven't had this combination on the dyno yet,in truth I regret being talked out of the 6:71,
But on the bright side,bigger valve heads,bigger blower,hopefully a lot more power !
Not going roller cam.........yet, not sure of centreline


Point of interest,Farndons of Coventry(UK) used to offset the cranks for TVR ,making them 5.0L, I set up a meeting with the manager about making me a billet steel crank,when I got there,he had all the TVR drawings on his desk,so my crank is a tried and tested,but a forged billet steel TVR crank
Thanks for all the replies

Bryan, FWIW the BDS chart says a 4-71 should make 9.57lbs. boost @ +10%, on a 302" motor. Crankshafts are either "forged" or "billet", never both. If your crank is 100% machined, on all surfaces, it's likely a billet. With a bigger blower and more boost, you "may" need (2) drive keys, on the crank. I would like a crank quote for either forged or billet. "Wildcat" is out of the question. Cheers, roverman.

Cranks 100% billet,
I was charged £2k for mine,had mine cross drilled and knife edged.
Should have the car (and engine) back on the road,after 4 years ! Going to run it for the summer,while I collect all the parts,work has started on my heads,
Hopefully Offenhauser will make the manifold of which you speak
Many thanks for your help
Bryan

Hmm, got a little confused there for a moment with a thread on a different forum, ergo the 4x4 reference, sorry about that. Surprisingly similar build though.

Anyway for your application it seems the lower static CR, higher boost, higher flowing head, high lift and duration cam combination is bound to yield good results on the strip. The TA heads are definitely something you should be looking at as a potential future upgrade since they have great flow potential and in combination with a roller cam (Art has some blanks) and a good set of roller rockers will really wake that engine up. In fact you might want to just consider a new build and swap in the crank when the time comes, provided you can match up the mains. What I'm thinking is that by the time you get to the big heads you'll be at the limits of the fasteners, or more specifically the threads in the deck. The bottom end is beefed up and you can install thread inserts in the deck but that'll only go so far. You might plan ahead for an iron block 300 or even 340 Buick based build. Even the 350 may be an option by then, as aluminum heads may be out in another 5 years, though considering that would require a number of incompatible parts I guess the 300 is still the best bet. Spacers for your intake to fit a 300 block are available, seems like TRS and Wildcat might have them.

The iron block is much stiffer and in the 350 version has seen 700hp levels without supplemental strengthening. (The blocks are nearly identical aside from deck height.) 1000+ with a halo girdle and block fill. So the 300 iron block would be a good starting point and thread pull becomes a non-issue. The weight penalty is 80 lbs. If you can accommodate that the benefits are great. Paired with the above upgrades including your blower your power output could go as high as double your last build without to much difficulty and should hold up well. Check over on the V8Buick forum as that site is frequented by drag racers and the small block Buick is a popular engine. Sean has my halo template and has a book that will be out very soon which outlines the very best of the builds done on that forum over the last dozen years or so.

Purchased bare, the TA heads at $1500 are affordable and have tremendous flow potential. Art will do right by you on the roller cam blank. Roller rockers from TA are expensive but other options exist, probably more over there than here. Not sure about the main size on your billet crank though. The 300 used a 3" main bearing where the 4.6 used a 2.5" size. Are bearing spacers reliable enough for a racing application? Should be if done right but really it's hard to say. That would take some research but I do believe it has been done. I would look into the early small block Chevy drag race engines using the production 400 CID siamesed cylinder wall iron block with the earlier cranks, as they had the same issue. I know quite a few of those were built so there should be a good record of how well they held up. I can't say I ever heard of it being an issue though and I believe the bearing spacers have become a stock item.

Jim



Edited 1 time(s). Last edit at 03/18/2013 01:57PM by BlownMGB-V8.

Correction, The 300 crank uses 2.50" mains. 340/350 uses 3" mains. Bryan, Stage I Buick valves by Manley or Ferrea, are possible with new seats,(suggested). This gives you valve dia's of 1.77" and 1.5", without moving valve centerlines.The problem with up-grading 300 heads is, time you do "all" the work, they are only slightly less than TA's. The TA head is muck stronger, has six-bolt potential and sbc pedestal rockers, may be used. At some point, with enough boost, you may need to consider a main girdle. Cheers, roverman.

Rather then start a new thread,I thought I'd update this one,
Here's what I started with

I've been collecting parts for a while,then I got UK Blowers to put this together for me

I've bought the bigger valves,springs,retainers etc for my Buick 300 heads,but a change in direction(tax rebate lol) these turned up from South Australia this morning !

I'm going to put the blower on first,run it for a while,the new heads will be going on over the winter,
The carb at present is a 650cfm QFT,do you think I will need to go bigger with the new heads ?
Out of interest my heads took 5 days to get to me,from Australia,got them from TRS

Good Show ! I think I'm seeing a 6V -71 ? I suggest Cometic gaskets or o-ringing, to handle all that new found power. Properly set-up, that blower should make up to 20 lbs boost. Make sure your "pop-off" is large enough ! Have Fun, roverman.

Yep 6v71,with Dean Blowers heavy duty bearing cases,large pop off valve on other side !
Cometic gaskets included with the heads,may O ring as my old heads

FWIW, TA's will swallow a 2.02" intake valve, with their standard centerlines. Power to the people ! roverman.

I bought mine complete,

Bryan, Valves angles and centerlines are "different" than oem RV8 or Merlin. This is criticle for the valve notches, in your pistons. Now, go kill some Chevies.... roverman.

The heads are on !(nearly)
Checked valve to piston clearance on all eight cylinders,no notching needed



Hoping to have it running by the new year on my old headers,but will be making a new set in the new year

Fantastic Bryan! Can't wait to see how those heads work for you,

Jim

Old thread I know, but is there a thread with the results of the combination described, somewhere?

The engine has been rebuilt with all new bearings,new pistons,rings,roller cam,heads have been ported,
It's been run in on the dyno,made 472bhp @ 6k with 12lb of boost,
More boost will be added,and the engine will/can Rev a lot higher,cam has more then 6 thou lift '
Once I'm happy with it,I will put full spec up !
Ignition is all in at 16*

Bryan, Good Show ! What octane fuel, or E85 ? 16* total timing, sounds a little short ? Cheers, Art.

A preview of what’s coming





Carbed at the moment,fuel rails in with dummy injectors,6:71 running 10% under to give 15lbs of boost

Injector hat by JoBlo Australia

Dry fitted

Will have a spacer fitted,inch high,two inches forward,
8 injectors in the hat,8 in the manifold,all new coil pack ignition controlled by by state of the art ecu,
Stay tuned for further developments