I mentioned in my build thread that I wanted to drop in a bigger motor with the sequential, but I've been thinking a lot about what displacement to go with. My ultimate goal is to run a 10.90 with the truck at full weight, spare tire and a full tank...around 5700-5800lbs. Elevation is right at 3000 feet at my local track, and figure in some extra heat since its Arizona. I realize it'll take a hell of a lot more than just power to get me to that ET (suspension will need some work too), but I plan on taking my time piecing this one together. Basically it just comes down to the bigger motor with less boost, or the smaller one with more boost.

 

The real question is how much do you want to spend?

 

I say 370. I've seen many people with 370's making the same power as a 408.

 

370 is capable if makeing same power as the 408 i agree but you gotta think about the torque needed to get 6000lbs moving
408 is the way

 

unless you want to use the stock crank Id say go 408. just my .02

 

If you're using the TVS as your blower of choice, I'd stick to 6.0L. A bigger engine won't do much other than bumping the tq up a little. You'll have plenty to get things moving with 6.0L's.

 

He has a turbo to take care of the top end air need, I say 408 for sure.

 

The weight, elevation and the current combination makes me say go with the 408 all the way. Normally I don’t particularly care for the 4” and larger stroke motors in an application where longevity is a primary goal with a stock block LS, but when all out performance is, they do get the job done and then some. That and I have to agree with the sequential boost Jake has going on that it should be a very impressive combination to say the least and I for one would be interested in how it turned out.

 

I'm splitting the difference and building a 383. I'm using a super cheap 5.3 bored to 3.905, a 4" crank and CP Bullet pistons of -18.2cc's. I just got the pistons today and I must say they are absolutely perfect forged beauties. I'll be running a compression ratio of about 9.7:1 under my 1900 blower. I know that the 383 will be stretching the Magnusen's output but I've read an old Hot Rod article that had one on a 402 that made nearly 700hp.

I like the stroker because of the torque and I like the displacement... halfway between the 364 and the 408. And besides, I haven't heard of anyone building a blown 383 yet. Gotta be different.

 

There are a few 383s, but there is a reason for that. A 383 in an iron block has all of the draw backs of a 408(piston instability) with none of the advantages(more cubes). IMO its not worth it for the extra 13 cubes. If youre going to do it, go with an aluminum block so some of the piston rock problem will not be as bad.