393 or 408 with 76mm turbo

2002BLGT

Well-Known Member
Dec 18, 2003
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Bedford VA
I am about to build a mild 393 or 408 for turbo setup , going to run Edelbrock performer RPM heads, Lightning intake with 93 cobra upper , 9.5 compression , with a precision 76mm turbo .......with probably a .550-.575 lift cam , what you guys think this will run and or dyno ?? Anybody got or ever seen a similar combo ......I know alot of guys will tell me to put bigger heads and intake on but I already have the heads and I know where I can get the lightning intake for about 150-200 bucks
 
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i would go 408 and skip on the lightning intake and cobra upper and just go big:D and go with the efi spyder intake elbow,my guess is the combo should be good for 600rwhp but will be higher depending on how much boost you run.
 
First off....what are you goals? What are you planning to do with the car? Street, Race, both? You trying to make a dyno queen, or are you wanting a performer? What's your budget for the engine....or better yet the entire project?
 
Id like to to run 10.0 or quicker quarter mile time , will probably ditch the T5 in favor of a PA or redneck C4 ......I will probably uprgrade the cam to closer to .600 lift and larger heads like afr 205s down the road , but as for now it will take every dime I have to get it up and going , the RPM heads I already have so thats why I am keeping them for now , I already have the cobra upper intake , and can get a good deal on the lightning lower thats why i was going that route for now ....
 
If it's gonna take all your money to get it done, why not do it in stages instead of doing it twice.
Skip the turbo for now, and do the shortblock, better heads, cam, and intake first.
With a 408 and no turbo with good h/c/i it should run mid 10's anyway.

Building anything twice sucks and is always more expensive in the long run.
 
If it's gonna take all your money to get it done, why not do it in stages instead of doing it twice.
Skip the turbo for now, and do the shortblock, better heads, cam, and intake first.
With a 408 and no turbo with good h/c/i it should run mid 10's anyway.

Building anything twice sucks and is always more expensive in the long run.

building it is part of the fun to me and mid 10s aint 10.0
 
You don't give enough detail. Why are you going with a 76mm turbo? Is it one you already have? If so, which 76mm turbo is it? Precision makes a GT42 based 76 and a 76GTS. What frame are you using and what is the hot-side A/R? Pretty much at 76mm turbo is going to be a quick spooler on a big Windsor. If you don't go big enough on the A/R you're going to choke the hell out of the motor. If I had to run a precision 76 on a big windsor, I'd personally go with a GT4276 with a T6 frame and a 1.28 or larger A/R.

As far as what it will dyno, it's up to you. I've seen a GT42-76 make 850ish rwhp through a TH400 and over 1000 rwhp through a T56, but these were both on smaller motors where this particular turbo is more efficient and not as choked on the exhaust as yours will likely be. You won't be able to do this with stock internals, either. The car with the TH400 went 8.76@15X mph. So if you want to run 10.0.... no problem

Chris