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4.1?

chickenfried

chickenfried

New member
so i bought my 99 gtp a few months ago and i love the car, but the guy i bought it from told me that him and his uncle from minnesota bored out the motor from a 3.8 to a 4.1. he said they changed the pistons and everything but i guess my question is... is this really possible to do? i know very little about motors but i am hoping to learn something by asking these questions, so please... cut me some slack!
 


For a while ZZP was selling a stroker kit that came with a new crank and rods to turn the motor into a 4.1. I suppose you could bore the motor out, and it is possible. That's a lot of displacement to get from just a bore job though.
 
its very rare to see someone actually use the stroker kit for our cars since its usually a giant waste of money. i honestly cant think of a way that youd be able to figure that out unless you took the motor apart.
 
Might be the stroker kit like mentioned above. I've seen the kit but have never seen anyone actually buy it and install it.
 


I work with a guy on weekends building Stage motors for Grand Nationals... the really, REALLY expensive ones are 4.1L strokers that put out 600-750 HP, depending on the customer's request. From my experience, the 4.1L mod is a very effective way to increase the torque of these motors. I don't have a lot of experience building up front wheel drive 4.1's, tho.
 
It's expensive and not quite worth it IMO. You can already get so much out of just the stock bottom end. Isn't the stroker a 4.2?

I've seen a couple of builds over on FTV6 and I'm not sure if anyone has put down any number yet.
 
just about everything internal to the engine is replaced. therefore, if you ever do break the motor in some fashion then getting replacement parts is not going to be cheap.
 


Pretty sure when ZZP did up their GT it was a 4.1...but I could have sworn the stroker kit that was more widely advertised was a 4.295, or 4.3...butI could be mistaken. I do know however...it was expensive...and for the price of that you could have gone way faster with an IC/Cam/Heads/Injectors/Tiny Pulley/Tune
 
If everything else is stock and it's actually 4.1, would there be a significant difference in the dyno? or 1/4 mile E/T? That's the only way I can't think to assume it has a larger displacement with out pulling the engine appart. Perhaps also lower PSI at peak RPM?
 


your not the only one. he said is uncle is a mechanic in minnesota and thats who helped him do it. but he does not have any reciepts or anything that gives written proof he did it. and i dont feel like taking apart the motor to check piston size. although thats what i might have to do.

if he did do this would that make it quicker than a gtp with straight exhaust, 180 t-stat, cold air intake, and 3.4 pulley? how would they match up?
 
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