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3800 Max Overbore?

M

MaineGP

New member
The title says most of it. How much over-bore can these engines take. Model year 2004. I would like to go at least .060" if pistons are available. More if the block won't end up with cylinder walls too thin. That also depends on available pistons. Possibly if I could locate or be pointed in the right direction to someone who supplies an over bored short or long block already done, I would go that route and not have to do the work myself. A bolt in swap is prefered. Thanks!
-John
 


any benefit from increased hp due to the larger bore is going to be negated by the extreme likelihood the engine won't hold together on startup. as far as I've heard, the largest bore you can do is .020. I knew a local guy who did a topswap and had his bottom end built and bored over at the same time. the car made 250 hp at the wheels because it was put together wrong, and never ran right again. the car ended up getting repossessed because he was dumb and spent obscene amounts of money on it.
 
Someone used to make a 4.2 stroker kit, might have been ZZP. But I'm not sure if anyone sold it already machined and ready to go.

Just with the amount of machine work needed on a regular 3800 just to make live past 200 miles makes this project really not worth it. The stock bottom end is already so strong that it's not worth the time and money to change it.
 


$4k will get you an Aluminum 3800 block bored to 4.000 and all the accoutrements...
: )

add in ZZP's AL Heads, a turbo and whoola... A serious street machine which no transmission will handle. You'll need to contact Dave at TEP and get a custom 4t80e tranny swap to take it all and put it to the ground ; )
 
jlbayes said:
if i have learned anything on here and tcg, stock is king as far as the rods, pistons and bore.
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@ the op guy. screw the boring and machining and stroking a 3800.....

this guy knows whats up. ^^^

stock is bestest stock is fastest slap a turbo on it and feed the b1tch some corn.

that will be plenty enough to destroy all the transmissions your heart could ever desire lol.

or go full retard and buy some 4k heads and some 4k "built bottom end" from say bully flo and still make less than a piddly turbo e85 setup. lololololol.

on second thought skip all the bullyflo drama too.

back my 1st point junk yard stock engine slap turbo on it feed it corn smile. then blow up transmissions and not smile.
 
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Travisgt2 said:
^^^^^^AGREE

or if you not looking for all that extreme hp: cam, hv3, exhaust, ported polished lim and heads, cat delete, egr delete, meth kit. easy 300 or more my guess
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No. It's not even close to 300 horse NA.

Stop it.

Local only made 212 WHP/220WTQ with Ported Heads and a GT2 cam with an HV3 and full 3" exhaust on a 3800 SE.

You're also not gaining ANY power from deleting the cat or EGR, unless it's currently clogged. Meth kit isn't needed on an N/A 3800. Just convert it to corn if you want anything better. 91 octane is plenty. I ran ignorant amounts of timing and a lean AFR in my silver with Efree93. It was running with GTP's with ease. Mods were in sig.
 
I do agree you wont gain power from deleting EGR but you will definitely gain power from a cat delete. The cat is a restriction, clogged or not. Hell I picked up 3 tenths in the quarter just from a cat delete on my Stealth back in the day. And no it was not clogged.
 


Perhaps certain vehicles have smaller restrictive converters but the 3800 converter is pretty free flowing and rather large, it's not going to reduce the flow on a nearly stock vehicle.
 
stealthee said:
I do agree you wont gain power from deleting EGR but you will definitely gain power from a cat delete. The cat is a restriction, clogged or not. Hell I picked up 3 tenths in the quarter just from a cat delete on my Stealth back in the day. And no it was not clogged.
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Stealth converters don't flow NEARLY as well as WBody ones. Older converters, especially. Most import cars see decent gains from converter deletes. I agree on the Stealth. Or a VQ car. Or some EJ boosted Scoob. Maybe even some 4G63 powered business. Not on a Grand Prix.
 
I've read that the max overbore should be limited to .030" and pistons are readily available. I think I'm going to go with the .030" overbore and stroker kit from TA performance. They say they can sell me a long block already done and include stage 1 or 2 heads if I want. Since I already have the Dynomax exhaust with the high-flow cat, I'll also add on the headers. The car is worth it because it is so pristine. It won't be as quick as my Challenger, but it won't be a slug either.

-John
 


MaineGP said:
I've read that the max overbore should be limited to .030" and pistons are readily available. I think I'm going to go with the .030" overbore and stroker kit from TA performance. They say they can sell me a long block already done and include stage 1 or 2 heads if I want. Since I already have the Dynomax exhaust with the high-flow cat, I'll also add on the headers. The car is worth it because it is so pristine. It won't be as quick as my Challenger, but it won't be a slug either.

-John
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almost positive you are talking about the turbo grand national and buick t type engines.....

those are ot interchangeable with the series 1 2 or 3 3800s
 
What? I thought all this stuff was the same as my 1984 Regal Turbo. It's not? WTF? I thought they just turned the engine sideways.
-John
 
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