im either going to build a new 383 ci ls1 for my rx7 or sell my current ls1 and buy a stock ls7 my goal is 550-600 fly hp and around 7k rpm which would be best for me?

 

I would go with a stock Ls7 personally. Cubes rule, and the ls7 can go to 7k without issue in stock form.

 

383 all day long....more simple engine internals...throw some arp rod bolts on and you're there for cheaper than buying ls7 components

If you're thinking about swaying from the ls1 then I'd do a sleeved ls2 and pull 454 cubes outta it reliably. You could also sleeve the ls1 and do a 427...many many options bro.

either way...you should burn that rx7 to the ground

 

Stock LS7 is a nice engine but you can likely put something together that achieves your goals of 550-600 fwhp for a lot less. 408 or so inches in LS2 or 3 block with good heads should get you where you want to go.

 

I have a stock ls7 for my car. I'll post up what it does in a few months. It should go over 500rwhp with bolt-ons.

What up Ken?

 

I wouldn't do a 383. I would do a 402 or 416 with aluminum block. Similar costs for internals, just need the block.

Ls7 is nice if you plan on doing basic upgrades. It's a good motor, but you can do more for less $$$

 

LS7 hands down

 

if you have the opportunity, go with the ls7. way better platform to start with and in stock form will meet your criteria while also being able to last 100k+ miles.

 

If you have the means, LS7 all day. More cubes=more reliable horsepower. It'll also spin up to 7K in stock form.

 

Depends on your budget. I like the idea of doing a 383 and having the extra funds for anything else you may need.

 

If money is tight, 383 all day.
But, my old man always said, "there's no replacement for displacement"

 

I vote for the 383 as you already have an LS1 engine and I prefer having an engine with forged internals even with a smaller displacement.

The 383 will reach your hp target and will help you if you wanted to spray in future. The LS7 is a great engine but it has huge torque.

For a light weight body like the RX7, I'd rather go with an engine with high hp and less torque.

 

yeah i see your points my current engine makes 480 fly hp and 490 ft lb i will never spray it or use forced induction i also have the chance to get an ls7 for the right price which is what is drawing me to it

 

If you can pull it off, an LS7 would be sick! Good luck either way

 

Ls7 duh!

 

Who else has an LS7 RX7? I would if I were you. . . . . .

 

Ls7!!!

 

Defiently LS7. I chose a 383 Alum block over a 415 Iron block and if I could do it all over again it'll be the 415. LS7 all the way if you have the pockets for it.

 

If I was building an old school SBC I'd definitely go 383 (you can go bigger but definitely have to shell out some bucks). But on the LSx stuff, go as big as you can within your budget.