Pros and cons stroker kit for 302?

Howard Jones

Supporter
Interesting numbers:

302 CI / 366HP = 1.21HP per CI

331 CI / 415HP = 1.25 HP per CI

347 CI / 450HP = 1.29 HP per CI

IMHO 1.3 HP per CI is just about the practical limit for pump gas. I bet every one of these motors are between 10.0 to 1 CR and 11.0 to 1 CR. Again a practical limit of pump gas. The Ford 302 crate motor is 9.5 to 1 CR and makes 345HP. My motor (Ford crate 302) with cleaned up valve pockets 302 X aluminum heads and a B303 cam was rebuilt with 10 to 1 pistons and well balanced made right at 307HP at the wheels.

289 at 1.3 = 375.7 HP
289 at 1.25 = 361 HP

Both 289 combos above would require near the 11 to 1 end of the range, big valve ported heads, and a fairly big cam.

I agree with Jac……………...again! Rebuild your 302 with quality hardware, balance it near perfect, and tune it well.
 

Chris Kouba

Supporter
The Ford 302 crate motor is 9.5 to 1 CR and makes 345HP. My motor (Ford crate 302) with cleaned up valve pockets 302 X aluminum heads and a B303 cam was rebuilt with 10 to 1 pistons and well balanced made right at 307HP at the wheels.

If I can read a little into this situation, it sounds like you're a bit in my boat. You want a decent motor to have fun with and use without too much fuss and worry. If I'm off with that guess, just disregard the rest of this post.

I also have the B303 cam FMS crate motor (iron block, alu heads; 345 hp, 345 tq) turning a ZF -2 box and am really happy with it. It moves the car very well, makes a wonderful noise doing so, and can do it all day long and then run me home through stop and go rush hour traffic. This is all personal tastes and expectations, but the combination is usable, tractable, pump gas-able, reliable, and very streetable. I have EFI on it and love it.

I personally don't need to have the biggest hammer on the bench but there are some people who do. I am probably near Howard with ~300 hp (realistically just under) at the rear wheels and can't imagine what the 500+ hp motors would do in these cars. If what you had was tickling your fancy, it seems like it's well matched to the rest of your drivetrain so why reinvent the wheel?

If you know you want to get more aggressive, it appears you have already answered your own question...
 

Ian Anderson

Lifetime Supporter
If you go stroker
Make sure you search on this site the discussions with Rod Ratio.

I believe Jac Mac has assisted the correct way.

Ian
 
I WENT WITH A 347. I FIND MINE TO BE VERY EASY TO DRIVE IN STOP GO TRAFFIC. 470 HP @ 6000 RPM 450 TRQ @ 4600 RPM . (MY HEADS HAVE BEEN PORT MATCHED AND I PICKED UP ANOTHER 20HP)

AT 3000 RPM I MAKE 220 HP SO MAXIMUM HP IS AT 6000 RPM. NOT MAY OF US DRIVE AT A CONSTANT 6000 RPM. HOWEVER, I MAKE 380 FT LB TORQUE AT 3000 RPM. NORMAL DRIVING I SHIFT AT 3500 RPM (260 HP)

SO 470 HP IS VERY EASY TO DRIVE ON THE STREET. AND I DO NOT HAVE TO DRIVE IT AT HIGH RPM TO MAKE POWER.

HERE IS A LINK FOR MY MOTOR SPECS

https://www.high-performance-engines.com/ford-347-stroker-complete-engine-450hp-p/hp100c.htm
 

Howard Jones

Supporter
Ya Chris, Walter, I have two cars. My GT40 has 350 odd HP and just keeps on going. It has enough power at the track to make the experience fun and yet there is very little maintenance beyond what would be necessary on a typical road car, abet at reduced intervals. I think the road performance is just about right. Runs cool, fuel range is good, suspension at a stiffness setting that is OK on the street, and other than the AC still don't work, pretty comfortable.

My SLC on the other hand is brutal stiff (and needs to be stiffer), the engine has a lot of cam and doesn't really want to idle under 1300 rpms, it uses 5 gals every 30 mins on track, and it makes about 500HP (350 SBC). Grip levels are not really comfortable for passengers at the limit on the R6 Hoosiers. And it is Hot (no AC) This is no car for the road as it is.

So what I am saying is there is no such thing as a real dual use car. If you make it go as fast as it can (slicks and big power motor) on track it really isn't good for road use. A milder road going car can be fun on track but not really as fast as it could be.

Having been thinking about this question for years now I think the best dual use GT40 ( biased towards the road ) would have a transaxle with gear ratios that include a useable 1st and 2nd gear and a 5th (or 6th) that runs the motor under 2700rpms @ 75MPH on the highway. The motor configuration would be selected to run on pump gas, use hyd roller lifters, make 375-400HP at 1.25 HP per inch (300-320 CI) very near a stand bore 302 or 331 (327 CI).

I would run 17 inch wheels, 8" F 10" R and very good summer only, 200ish UTQG, radials. AND not use a roll cage with a front hoop and center tubes. Cold AC is clearly a must.
 
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HOWARD... I HAVE AN 01E GETRAG BUILT BY SCOTT 1ST GEAR IS LOW AND IT IS A 6 SPEED.. 1800 RPM @70 MPH 15 INCH WHEELS
ALL SEEMS TO WORK WELL.. PLEASE UNDERSTAND THIS IS MY FIRST GT40 EVER
 

Dave Hood

Lifetime Supporter
I agree with Walt. I've got 15,000 miles on my 347 stroker engine and have enjoyed it on both street and track. A pleasure to drive.
 
Just my $.02 here.

I have had 302's, 331's and 347's...all in various states of tune, carbs, injection, basic stock and also with better (forged) pistons/rods/etc. Have worked on putting these together myself, not paying someone else to do the hard work so my experience is 1st hand.

The 347 puts out great torque when done right, but the stroke is getting a bit long so high rpm isn't it's strong suit. A good 302 is a reliable gem and will happily turn up to good rpm with the right components. The 331 is a nice compromise in my view with good torque in the 400 range and still will turn up to 6,500 rpm pretty nicely in a street form.

For your rebuild, buy good components, spec and measure everything, and put it together slowly and carefully and you'll be happy with the end result.
 
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