Junkyard GT40P 331/347 Stroker Setup

oxemoron

New Member
Jul 12, 2003
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I have the oppurtunity to get a complete explorer engine for free. I was considering machining the heads and intake manifold and bolting them on my 302 for now. Then start up on the block and build up a 347. Would the machined GT40P parts work correctly on a 331 or 347? Im trying to achieve low 13s with the machined bolt ons on my 302 and hoping for 12s with the 331 or 347. Is this possible?
 
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I would just swap the whole motor, if the bottom end of the explorer is still good, it would be easier that way. GT40 heads will work on a 347 just fine, but are small, so porting them might be a very good idea.
 
I've got a friend who has that exact same setup....not an Explorer motor but he does have a 347 with GT40P heads on it. His intake is a knockoff Performer, so he's probably left a few peak hp and tq on the table but he dynoed just at 300hp and close to 400tq, and the heads are bone stock with stock rockers.

You can cam out an Explorer motor and run 12s on slicks.
 
Awesome, then it seems like my goals are realistic. My car only has 44,000 miles on it so I'm in no rush for an engine swap, but i would like to be able to run with my friends low 13 high 12 second cars. So with a little luck, full exhaust, cam, machined gt40 heads and intake I'm hoping that wil get me there. Then I do plan on building the engine either a 347 or 351 Windsor. The 351 would be more likely because it would cost less, or so it seems. I wasn't sure if the machined gt40p parts will flow good enough on the 351, any ideas? Is there any difference as far as flow requirments go between a 347 and 351?
 
I'm doing this same combo. My original plans of a budget 302 went adios when the intake valve wouldn't clear the stock exploder pistons. There are no pistons made with deeper valve reliefs that weigh the same as explorer pistons. Some crappy hypers within 25 grams were the closest. Balancing was required.

Bushed rods, forged pistons [yeah, I might wanna spray it] and balancing were in the cards:eek: ...so a crank, balancer and flexplate seemed like chump change.

Now I have all the parts for a 342. Probe flattops with 10.5 compression and 5.315 rods,comp xe-266 cam, ported p heads with 1.84/1.54 undercut valves and ported explorer intake.

My only fear is the compression might be too high with the smallish cam and high velocity intake/head combo. Torque should be incredible, which is what my 4000 lb car needs. Tuning for power and cheap gas will be fun.

I should have it all together and dyno tested within a few months.

Seems like a 351 swap would have been a better plan for me $$$ wise:bang:
 
Originally I was going to just install the explorer motor, but it looked kinda crusty. One thing led to another. I had a matched combo for a 302 until the intake valves wouldn't clear the pistons. Good thing they didn't clear since at least 1 wristpin was slightly galled. 42 extra cubes was cheap after buying quality pistons.

The car runs a 14.7 @ 92mph with shorty headers and explorer intake. The engine is the original stock '93 tbird motor with 130k+ miles. The valve covers have never been off. 13.7 would be enough for a daily driver and just breaking 13's in my boat is the goal. Some spray for 12's is a possibility.

I'm just wondering if anyone has a similar setup and how it runs??????

My guess is a 5500 rpm turd with tons[400 lb?] of torque and 350 fwhp.