ok, say i wanted to ultimatly go with a 383. would i get higher power gains if i had a lt4 conversion first or will the lt1 yield the same results when you make it into a 383?

 

383 LT4, are you talking about an LT1 with mainly stock parts though?

 

well the thing is i have my car thats pretty much stock, going to add bolt ons and such but ultimatly i am going to bore /port n polish it to a 383. i was just wondering if i where to get a lt4 kit first, THEN port it, will i come out with higher power then if i where just to go strait to a 383 with the lt1
i was unsure though if the lt4 cams and heads and stuff where a waste since i am just going to port them anyways.and if there are better cams/heads available if i where to do so.

 

In theory if you coverted your engine to an LT4 and then did all those mods then you would get more power then if you just used a regualar LT1.

 

Dang, first an LT4 conversion and than a 383 build. You are looking at spending big money there.

 

Here is how they'll rank.

383 LT1
383 LT4 ~370rwhp depending on cam exh ect.
383 LT1 P+P heads
383 LT4 P+P heads Potential for ~440rwhp with a good port job and right combo

The LT1 P+P heads should be right in the middle of the LT4 stock and P+Polished.

To sum it up your better off porting your LT1 heads than doing the LT4 Conv, however there is more potential in the LT4 heads if your going to get them P+P'ed.

 

I wouldn't waste the money on the LT4 conversion because the only thing you'll want to reuse is the heads(after porting)/intake and it's just not going to get you that much more power in the long run. If you looking to other heads besides the LT1 then you'll want to go with AFR's.

You'll have to have it tuned twice, and you'll be spending money on things like lifters and gaskets twice, it just not worth it.

 

just have your machine shop 4bolt main splay your lt1 when you have it machined for a 383. It is stronger than the LT4 4 bolt main.

 

I would order the LT4 conversion kit from Year One. They have the kit that comes with the LT4 parts along with other modified parts. The kit is rated at 425 hp. You would still be able to do a 383 build if you wanted, but I wouldn't see a need to.