Seems alot of folks here are building 370s with LQ4 or LQ9 blocks for N/A,N2O or FI.

I read GM High Tech Performance religiously and a 3.90 crank has has been mentioned several times.

With a +.020 overbore and a 3.90 crank a LQ4/9 could be made to be a 396 CID, with a +.030 overbore and a 4 inch crank is a 408, An additional +.010 overbore same crank 410 CID, same overbore and a 4.1 crank is 420 CID.

Is it purely economics that dictates 370s as opposed to biggier strokers?

Wouldn't a 396 or 410 engine make more HP/TQ and work less even with FI or N2O than a 364 or 370?

 

Keep the stroke at 4.00.
408 takes my vote

Where to find that crank?

 

Well if u look at it like this, When the ls1 came out it carried a 3.622 crank and a 3.89 bore or something like that. Over the years the crank has stayed the same but a increase with the bore, Ls2,ls3,ly99 lq9. The ls7 has a 4.000 crank. With the standard stroke from gm and the increase in bore size power still came up. Hell there are some ls2,ls3 l99 blocks make 500 hp to the wheels with cam and head work. As far as construction of a 4.000 stroker I would look into sleeves just because the stanadard Gm sleeve is not long enough for a 4.000 stroke. Now do not get me wrong it works, But When it comes to stroker motors Id prefer more bore than stroke, Just for the simple fact that Gm heads D shape flow a ton of air, not very fast but they still flow. With the bigger bore less stroke sky is the limit on valve size with out shrouding the valve with the proper piston choice. NA stroker motor need the best flowing heads and intake combo and cam selection to make good hp unlike FI motors. Now mix the best heads and intake with a FI motor with the proper size turbo and so on you can see a 370 make 900 hp on 18 psi or a real budget 370 take 23 psi to produce the same amount of power.

Im not going to say what is better in the stroke area of a short block but, Id love to see a 396 lsx with some mast ls3 heads and a good cam power numbers and tq curve. I think it can produce the same power as a ls7 with the tq curve alittle higher.

 

I'd recommend an LS3/L92 block with the 4.065" bore cleaned up to 4.07" and the new 3.825" crank AES sells. 398" . Pick your heads and go FI if you'd like.

 

I think economics has a lot to do with the 370's being popular. Using stock GM crank saves bucks that can be spent on better heads.

 

I agree, seems like the smaller cubes370-396 are catching up with the 402-416 in hp but not tq But it is all in the build and money.

 

I'm almost forced to go the 370 route with the LQ4 I have unless i skimp on heads/intake, which i refuse to do. If I can break 475whp N/A through a 4l80e and S60 i will be a happy camper, then add spray accordingly

 

What I've seen on the internet and in print is stock block v.s. stock block the LQ4/9 is strongier than the LS3 or LS2 but heavier by about 60-65 lbs.

 

This is true due to the fact that an LQ4/LQ9 is an iron block whereas an LS2/3 are aluminum

 

If Pred had not said it, I would have. No need to go over a 4.00" Stroke crank.

On a personal level I never had much success with deep stroke or even long rodded motors whether it be the piston coming out of the sleeve or the extra pressure on the cyl walls due to rod ratio.

They certainly had benefits but the longevity was always IMO an issue.

What I have been learning is "Just because you can, does not mean you have to...."

 

The 3.825 inch stroker crank sounds like a good option especially when paired with a 4.02 bore this would allow for a 388 CID engine.

Despite the weight penalty I like the iron block LQ4/9 as opposed to a resleeved aluminum LS1,LS2 or LS3 block or LSX race block.

 

The 390 shortblocks (3.825 stroke & 4.030 bore) from AES look like a good value power maker. I'm thinking along those lines with a D1 or a TVS2300.

 

For a given stroke, longer connecting rods lessen the stress (side loading) on a cylinder wall, not increase it.

 

For me it isn't economics at all...my 370 has an expensive forged crank in it...for me...I wanted the bottom end to be strong and reliable...a shorter stroke keeps the piston speed down, and also keeps the acceleration of the pistons a little less agressive...you can build a big stroke engine thats strong...but this way made more sense to me. The other thing the 370 allows me, is a lower pin in the piston than a longer crank would allow, which gives me more room for the ring lands

However, I do agree, I think for most people...you can pickup an LQ4 for really short money, keep the stock crank, bore the block .030, and you've got a 370 for not much money...

 

I built a couple 283's back in the day and nothing since. Back then it was all about c.i., dual quads, 4 speeds and low gears.

When I see 370 c.i. it sounds small and this build I gotta have bragging rights to 1000hp. Can that be done on 370 w/a stock crank?

 

I don't see why you can't make 4 digit power on 370 cubes and a stock crank...the stock crank is a pretty dam stout part...I don't WANT to push one that hard...so I went forged...but I think it can take it...cam it correctly, with the right heads, and the right CR and the right boost, and the right tuning...and so on.

 

To minimise some of the machine work that 3.8 inch stroker crank sounds like a good idea, especially when teamed with a 4.005 bore iron block(383 cid).

I don't know but I hear the stock 3.622 inch stroke crank is good for 1000HP.

Would be fun to see what a 383 would do with a F1-A attached to it.