Is this a 302 or a 347 ???

Finally got around to sorting out documentation that came with my GT40 and I found the dyno printout from late last year. So thought I might as well post it up here. I got told it had 320 rwhp, dyno sheet actually reads 315.2 rwhp, close enough I suppose.

Some confusion reigns over what the actual cubes are for the engine fitted to my GT40. Word of mouth says that it is a 302w with a nice performance build. I don't have any receipts for engine build but I do have a detailed quote for it and it was spec'd as a 347. Quote is from engine builder that built the engine and all external stuff matches that of quote. Interesting... I will have to get around to measuring the stroke one day. The only other useful piece of documentation I have is the Crane Cam card.

Anyway going on information below what does your gut feeling tell you, is it a 302 or a 347 stroker?

Basic Engine Specs:
Trick Flow Alloy Heads 2.02" Intake, 1.60" Exhaust
Crane Hydraulic Roller Cam 2031
Intake - 302 @ valve 513
Exhaust - 311 @ valve 529
Rocker Arm Ratio 1.70
Yella Terra Street Roller Rockers
DC&O 8 Throttle Body Manifold
EMS Dual Sport 2 ECU


315.2 rwhp with Dyno Dynamics dyno
which should equal around 362.5 rwhp on a Dynojet dyno.

Interesting that a guy in Cobra Club got a carby 347 dyno'd at the same shop and it produced 310 rwhp. I'm a bit of a believer in dyno's as just tuning tools, but hey it's always fun to throw around tuning figures.

Currently it drives really well, even has a nice smooth idle. Exhaust sound is a little embarrassing as it does sound like a VW and I will upgrade the exhaust on it soon, which should make some HP improvements. /ubbthreads/images/graemlins/smile.gif
 

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Neal

Lifetime Supporter
Craig,

I've built a number of 302 and 347 motors using stock trick flow heads and a variety of cams.

Stock Ford 302 lower end w/ trickflow heads, TFS EFI intake and 221 intake/ 225 exhaust .499"/.510" = 300rwhp / 310rwtq

347 lower 9.5:1 compression / stock trickflow heads / 224 intake/ 232 exhaust ..542"/.563" - TFS Track Heat EFI intake - 365rwhp - 350rwtq

347 - lower 10:1 compression / TFS heads with port match and valve job / 224 intake/ 232 exhaust ..548"/.562" / 48IDA weber carbs - 462FWhp - 455FWtq (No rear wheel measurements yet)

Your numbers seem low based on your induction and cam timing... Pull a plug and measure the volumetric displacement.
 
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