Engine and Transmission Tech

Taking some inspiration from your very own Greg Myer in this article: [www.britishv8.org], I'm looking for some advice and experience increasing the performance of my stock 1969 Ford 302 V8 whilst retaining a completely stock look externally, i.e. by modifying the engine internally and invisibly only, which also includes retaining a 2 barrel Autolite 2100 carb. I want to see how far beyond my motors original 210HP I can get. I'm planning the following internal upgrades:

- Changing to a 1.33 venturi Autolite 2100 2v carb for 424CFM (up from the stock 1.08 venturi 287CFM) on stock intake
- 347 stroker kit
- Porting and polishing standard iron cast '69 heads with 1.60" exhaust and 1.94" stainless steel intake valves
- COMP Cams Ultra Pro Magnum 1.6 ratio 7/16 stud mounted roller rockers with Crower 0.865" short Polylocks (purely to clear stock valve covers)
- COMP Cams retro-fit roller cam and hydraulic roller lifters - something with a mild street performance, perhaps a 260/270HR?
- Hypereutectic aluminium pistons and increasing compression ratio to 10:1 on premium petrol
- Hi-po 289 cast exhaust manifolds (yes I know they're visibly different but still look pretty stock...)
- 2.5" dual stainless steel exhaust with an X crossover pipe and Magnaflow mufflers
- Port matching the standard 2v intake manifold and gasket to the ported heads
- Pertronix Igniter points and coil replacement (will also do new HT leads at the same time)
- K&N air filter

The engine is fitted to a Ford AOD automatic transmission and in 4th @ 65MPH revs at about 2,200RPM with a 2.79 rear gear ratio. I'm a weekend cruiser so not looking for high RPM HP, will likely stay below 5,500RPM, I mostly want off the line torque.

I have the following questions I'm hoping for some advice on:

1 - Will I ever unlock the full potential of a 347 stroker kit restricting myself to the original 2v carb even if I'm increasing flow to 424CFM? Or is there a decent benefit to it anyway?
2 - Is porting, polishing and matching the heads and intake manifold going to achieve anything or just hurt low end torque?
3 - Likewise increasing the valves to 1.60" exhaust and 1.94" intake? I'm retaining the stock 2v intake manifold.
4 - Have I missed any other 'invisible' upgrades that would make more sense or are worth doing as well?

Much appreciate any advice you guys can give!



Edited 3 time(s). Last edit at 12/29/2017 03:33AM by RudyK.

Rudy, For longevity without oil burning I'd go with the 331 kit. The 347 oil rings go through the piston pin hole. I'd get a set of GT40 heads with stock valves and look at Alex's parts for drop in HP valve springs. Breathe much better. Dura spark 85 Mustang distributor with small cap using GM HEI 4 pin module.You will have to use bigger jets in carb.

Rudy, cool build. I like the sleeper concept.

Jim. I'm guessing Rudy isn't in the States, so he's going to try to use the heads he has. I would have recommended some 66 C6OE small chamber heads, but, as Jim recommends, the F7TE are the best heads from Ford. If you stay with the 69 heads, you'll want to convert the rocker studs to screw-in type. I'd be using beehive valve springs.

Zero-deck the pistons to make the most of the quench-type heads.

I also think the 331 kit is a good idea.

If you can get some 69-70 351 exhaust manifolds, they are slightly larger than the stock manifolds. You can port the exhaust manifolds. Look around for David Vizard's research on porting exhaust manifolds for ideas.

To answer your questions;
1: The smaller carb won't hurt performance until you get into higher RPMs, The stroker crank will give more low RPM torque.
2. Porting won't hurt. I wouldn't put much effort into 'polishing', just doing a 'pocket port' to improve the area under the valve, and port-matching the runners.
3. Bigger valves won't hurt but if you went with 1.84/1.55 valves, you could use 351 valves.
4. No, you're on the right track. You could build it exactly as you describe and it would be a nice performing engine.

The Autolite carburetor is a nice part. The way you are setting up this engine would allow easy conversion to 4bbl without having to change anything except the intake manifold and carburetor (if you use another Autolite carb like the 1.08 4100).

Fun!

Many thanks for your replies so far guys, very helpful indeed.

Jim, I hadn't considered a 331 stroker until now, wasn't actually aware of the oil burning issues with the 347. I'd like to retain my existing '69 heads as they're (mostly) period correct to the car, same with the distributor.

Paul, you're correct, I live in England. The heads I've got are the D0OE-B 58.2cc ones which are being converted to 7/16 screw in rocker studs. I considered '69 351 exhaust manifolds but they're even wider than the 289 hi-po's I've got and didn't fit.

I'm looking forward to the results, thanks again!



Edited 1 time(s). Last edit at 12/30/2017 01:37AM by RudyK.

> I want to see how far beyond my motors original 210HP I can get.

Be aware that 210 HP was an SAE gross rating. At the time, Ford advertising had three ratings to choose from. Engines like your 302-2V used the "Engineering A-Curve" power. That was the maximum output you could get out of an older engine (looser clearances than a new one) without accessories and with dynamometer headers. The B-Curve was the engine as installed but without accessories. The "Engineering C-Curve" was essentially what became the SAE net (as installed with all the accessories and full exhaust). By 1972, the 302-2V engine was rated at only 141 HP SAE net @ 4000 RPM and that's before the loss through the transmission and differential.

I have the dyno data for a 1969 302 that was tested on Ak Miller's chassis dyno. The engine tested was in a Detomaso Mangusta and was essentially a 302-2V fitted with the 1.08" venturi Autolite 4 barrel carb. Those cars got the lower 9.5:1 compression 302-2V long block due to lower octane fuels available in Europe at the time. In stock form, it made 110 RWHP @ 5500 RPM. With larger valve 351W heads, 10.5:1 compression (domed) pistons, a C90Z-6250-C cam (essentially a hydraulic lifter version of the 289 HiPo solid lifter cam with 290 deg seat duration and 0.470" lift) it made 145 RWHP. With a larger venturi 4100 Autolite carb, it made 155 RWHP. The Mangusta used shorty tubular exhaust manifolds and fairly restrictive mufflers so I'm sure that held things back somewhat, as did the low rise 4 barrel intake manifold.

> Changing to a 1.33 venturi Autolite 2100 2v carb for 424CFM (up from the stock 1.08 venturi 287CFM) on stock intake

Be aware that 2V and 4V carbs are rated at different pressure drops. 4 barrel carbs are rated at 1.5" of mercury while 2 barrel carbs are rated at 3.0" Hg. The reason for this is primarily historical. When 4 barrel carbs first came into popular use, the vacuum pumps used to rate 2 barrel carbs were unable to pull the same pressure differential across a 4 barrel carb, so 4 barrels were rated at a lower pressure drop. Since the volumetric flow rate for an incompressible fluid through a venturi is proportional to the square root of the pressure differential, flow ratings from one standard can be related to flow ratings from another. For instance:

Flow @ 1.5 In Hg = (CFM Rating @ 3.0 In Hg)/SQRT(3.0/1.5)

So a 2 barrel carb that flows 424 CFM (at 3" Hg) only flows around 300 CFM when tested like a 4 barrel carb at 1.5". Furthermore, the Autolite flow ratings are optimistic. One of the guys on the FE Ford forum tested a series of Autolite 4100s with the larger primary venturis that are claimed to flow 600 CFM but found them to flow between 502 and 528 CFM at 1.5" pressure drop. The smaller venturi version used on 289 SBF V8s flowed 441 CFM.

> Will I ever unlock the full potential of a 347 stroker kit restricting myself to the original 2v carb even if I'm increasing flow to 424CFM? Or is there a decent benefit to it anyway?

For the reasons noted above, you will not seen anything near the full potential with a 2V carb. Also, the larger the venturis get, the poorer the atomization will be at idle and low RPM so it may actually get a bit more sluggish with a larger 2V carb.

> Porting and polishing standard iron cast '69 heads with 1.60" exhaust and 1.94" stainless steel intake valves

> COMP Cams retro-fit roller cam and hydraulic roller lifters - something with a mild street performance, perhaps a 260/270HR?

A cam matched to your combination will help you maximize the performance but the limited induction and cast iron manifolds will limit how much you can expect from a cam swap. One of the primary benefits from a hydraulic roller is the ability to reliably run higher lift. In unported form, your heads are pretty go flat at 0.400 to 0.450" lift. Porting and larger valves will help that.

> Hi-po 289 cast exhaust manifolds (yes I know they're visibly different but still look pretty stock...)

The short runners of cast iron manifolds will give up a bunch of peak torque. I've dyno tested 351C engines which have large port iron manifolds and gained 36 HP and a similar amount of peak torque by switching to long tube headers. You won't see as large a change as that on a Windsor with OEM heads but its still significant.

You may want to read the SBF section of the old 1970s Ford Muscle Parts catalog where the detail outlined 3 levels of changes for the 289 and 302: Impressor, Controller and Dominator with HP increments for each change relative to a stock 289-2V. Adding the C90X high rise dual plane intake, 600 CFM Holley carb and an open element air cleaner was good for 31 HP. Adding the C90Z-6250-C hydraulic cam with matching lifters and springs, along with a 289 HiPo dual point distributor was worth 40 HP. Adding tube headers was worth 15 HP for a total of 86 HP over the 200 HP 289-2V. With these parts in place, the larger port and valve '69-'70 351W heads and 10.5:1 compression pistons were worth 32 HP. Larger GT40 valves added 7 HP more for a total increase of 118-125 HP over the 289-2V. Switching to a Lemans solid lifter cam brought the total increase to 144-155 HP over the base 289-2V. Going from a 289 to a 302 was worth 11 HP. A digital copy is located here:

[www.mustangtek.com]

The parts they used are obsolete but the sequence of changes and results may be informative.

> 2.5" dual stainless steel exhaust with an X crossover pipe and Magnaflow mufflers

Magnaflows are excellent mufflers. With a 2V induction and cast iron manifolds, 2.25" would be sufficient but 2.5" would give more room to grow should you decide to upgrade your intake and exhaust.

> Port matching the standard 2v intake manifold and gasket to the ported heads

I've not tested any 2V intakes but most of the 4V dual plane intakes have one plenum half that flows quite a bit worse than the other. You'll need to have access to a flow bench to tell which one is bad. On some intakes the upper plenum is worse than the lower. On others it is reversed. In any case, blending the plenum entry on those cylinders and/or lowering the divider can bring the poorer flowing cylinders up to nearly that of the better flowing. Beyond that, you could have the intake manifold Extrude Honed but that's quite expensive.

> Pertronix Igniter points and coil replacement (will also do new HT leads at the same time)

The single point distributor doesn't give full advance until nearly 4000 RPM. You'll want to re-curve the distributor to bring in full advance earlier. Somewhere around here I may have a package of MSD springs that I can get the part number off of. If you go with a steel core roller cam, you'll want to swap out the distributor gear for a steel gear. The OEM Ford gear from the fuel injected engines won't work as those distributors had a larger shaft OD. I believe Crane makes the correct diameter steel gear.

> K&N air filter

Duct cold air to it.

> I mostly want off the line torque.

A small primary 4 barrel carb and set of long tube headers will do that better than a 2 barrel carb and iron manifolds, especially if they are matched to more displacement, decent flowing heads and an appropriate cam.

> Is porting, polishing and matching the heads and intake manifold going to achieve anything or just hurt low end torque?

Done properly, porting won't hurt low end torque. As others have noted it would be better to start with stock appearing GT40P or GT40 heads. With those heads, you can use pedestal mount roller rockers and they already have hardened seats. Before you have your current heads modified, figure up all the machining and labor costs (milling for studs and guide plates, hardened seats, oversize valves, guides, porting) and decide if the expected results are worth the cost.

You might consider build a "day two" build, something that appears period correct (as if the guy built the engine on his second day of ownership after bringing the engine home from the dealership in 1969. You could use some of the Ford muscle parts from the day (C90X dual plane and tri-y headers).

The ring intersecting the oil pin being a problem with 347 is mostly an old wives tale. We've had no trouble with oil control. My engine guy does a lot of 289 and 302 builds for classic Mustangs, Cougars, Tigers, Broncos and the like. He likes to a use modern thin ring package. He also builds 2 barrel carb 302s with GT40P heads for a rules restricted circle track class. If you decide to stay with a 2 barrel carb build, I can pick his brain for ideas. IIRC, he found some power swapping in the boosters from a Holley 4100 carb into the Autolite housing. I believe the 4100 boosters are slimmer so provide a bit more CFM.

Dan Jones

Rudy, I agree with everything Dan says except "old wife's tale" on the 347. Some kits went to a shorter 3.315 connecting rod and 331 pistons to solve the problem. Others went to an improved piston/ring setup. So you have to shop carefully. I know 10 years ago it was very much an issue.

Dan, many thanks indeed for your very comprehensive reply, much appreciated!

> Be aware that 210 HP was an SAE gross rating. At the time, Ford advertising had three ratings to choose from. Engines like your 302-2V used the "Engineering A-Curve" power. That was the maximum output you could get out of an older engine (looser clearances than a new one) without accessories and with dynamometer headers. The B-Curve was the engine as installed but without accessories. The "Engineering C-Curve" was essentially what became the SAE net (as installed with all the accessories and full exhaust). By 1972, the 302-2V engine was rated at only 141 HP SAE net @ 4000 RPM and that's before the loss through the transmission and differential.

That's really interesting. My car currently has a '79 302 2v installed in it rather than the '69 original that I'm trying to re-create. I had that '79 engine dyno'ed in the car with the following minor mods: '79 EGR cast intake manifold, EGR spacer and 2150 2v carb replaced with a '69 cast intake manifold, regular spacer and '69 1.08 venturi 2100 carb. Stock '79 exhaust manifolds replaced with 289 hi-po's connected to 2.5" dual Magnaflow exhaust with an X pipe. That combination made 183.7HP @ 3,434RPM at the rear wheels and 284.9 FtLB of torque @ 3,361RPM (see attached photo). Doesn't sound too bad a result considering the cripplingly large cylinder head chamber sizes in '79.

> For the reasons noted above, you will not seen anything near the full potential with a 2V carb. Also, the larger the venturis get, the poorer the atomization will be at idle and low RPM so it may actually get a bit more sluggish with a larger 2V carb.

So perhaps it makes more sense to stick to the stock 302 crank/rods and maybe just nudge up the compression ratio from stock 9.5:1 to 10:1 with +2.5cc domed pistons? Also, my idle is quite high anyway as it's an automatic.

I understand all the advice to ditch the 2v carb and intake manifold and move up to a 4v, but I'm determined to keep the car a 2 barrel to be visually 'correct'.




Edited 2 time(s). Last edit at 01/05/2018 12:29PM by RudyK.