370 OR 408 for boost?
Staging Lane
Joined: Feb 2010
Posts: 73
Likes: 0
From: LI.NY
Dude, put down the 1970's Hot Rod magazines. Have you ever even run a 3.62" stroke ls vs. a 4.00" ls in your own personal stuff? Or are you just following the old saying that "short stroke motors rap faster"? lol
I was put in this predicament when I was assembling my motor. I talked to quite a few guys and they all seemed to agree that a 370ci engine would be a better engine. It has a lot to do with piston speed (based on how much stroke you have) and volumetric efficiency. Not saying that a 408 can't make more power, however it seems to say that a 370ci is more likely to stay together due to its shorter stroke and has a higher rev potential due to having a lower piston speed. The reality is either one will get the job done so don't sweat it. If you don't mind paying a little more a 408 will have torque lower in the power band a 370 might rev a little higher. Its pretty much a wash until you get to power levels that you shouldn't be running a factory block.
Staging Lane
Joined: Feb 2010
Posts: 73
Likes: 0
From: LI.NY
Seems a happy medium is a short stroke 390". More Tq should be nice on the street out of boost. Just would like someone that has a boosted 390 to chime in. After researching this WAY too long now. No real good reason to go 408. If I were N/A, Then yes, 408. So anyone on a shorter stroke with an F series?
Seems a happy medium is a short stroke 390". More Tq should be nice on the street out of boost. Just would like someone that has a boosted 390 to chime in. After researching this WAY too long now. No real good reason to go 408. If I were N/A, Then yes, 408. So anyone on a shorter stroke with an F series?
Staging Lane
Joined: Feb 2010
Posts: 73
Likes: 0
From: LI.NY
Thank You! I tend to Way Overthink things like this.
TECH Enthusiast
Joined: Oct 2007
Posts: 530
Likes: 2
From: South Lyon, Michigan
I'd suggest talking to a builder. Have them recommend you something that gives you what your goals are.
Personally I like the idea of a short stroke, big bore, with mild compression. (11.5:1 area) and hang a turbo on it that'll support the power you want to make.
There's plenty of blocks, head and camshaft people out there that can make anything you want to do based on your budget and goals.
Personally I like the idea of a short stroke, big bore, with mild compression. (11.5:1 area) and hang a turbo on it that'll support the power you want to make.
There's plenty of blocks, head and camshaft people out there that can make anything you want to do based on your budget and goals.
This reminds me why I don't read and answer questions on here anymore... So much misinformation it's silly.
For one pistons aren't made any different now than they were 10yrs ago. The piston design has little to no affect on how far it comes out the bottom of the sleeve with a 4" stroke crank. I would never build a 408 street engine with boost especially with a pissy *** T4 76mm. The 370 with that size turbo will make more power and run faster. The 408 will spool the turbo quicker no doubt but it's also gonna run out of steam and choke up faster too. If I was building a stroker it'd be in a newer block with longer sleeves or in a LSX block. And at that point it'd be using a GT55 based or larger single or twin 76's or larger.
Ultimate combo for the money is the 370 with a single billet S48x from Jose. That combo will easily surpass the goals at hand here.
For one pistons aren't made any different now than they were 10yrs ago. The piston design has little to no affect on how far it comes out the bottom of the sleeve with a 4" stroke crank. I would never build a 408 street engine with boost especially with a pissy *** T4 76mm. The 370 with that size turbo will make more power and run faster. The 408 will spool the turbo quicker no doubt but it's also gonna run out of steam and choke up faster too. If I was building a stroker it'd be in a newer block with longer sleeves or in a LSX block. And at that point it'd be using a GT55 based or larger single or twin 76's or larger.
Ultimate combo for the money is the 370 with a single billet S48x from Jose. That combo will easily surpass the goals at hand here.
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