My LT1 is on it's way out and it's time to start looking for something new. Basically I'm looking for an emissions legal 400hp-475hp bulletproof engine. I'd like to have as little downtime as possible meaning I'd probably buy a nice block and do the rebuild in the garage on the side.

I'm basically trying to get a feel for what I'm going to need to buy in order to make this happen. Are there engine kits I can buy? What's a good block to start with? Would I be better off just buying a crate engine? If I build the engine what are a few companies that make quality heads?

Thanks for your replies.

 

Not really an "Advanced" question

But....if you're going to do the assembly yourself, it's really how much you want to spend. If you're only looking for 400-475HP, I wouldn't suggest spending $5K+ on the rotating assembly.

www.cmotorsports.com has some good stroker kits in the $1800 price range for your basic forged 383. You'll need to spend a good chunk of your budget on the top end to get to the upper part of the power you're wanting.

Check with Seth at the link above or talk to Brett Bauer (SStrokerAce) and see what they can do for you on a rotating assembly.

Don't forget to have the block clearanced.

 

You need to clarify a couple things. When you say "400hp-475hp", are you talking flywheel HP or rear wheel HP? Are you trying to live within any sort of budget? Is it s "daily driver", a race-only or some combination of both? What emissions regulations do you have to meet, it any?

Taking a step away from the LT1 block is a major decision. You are pretty much committing to either a carbed Gen 1 SBC or an FInj setup using an aftermarket ECU. Can you tolerate the issues of cramming the distributor of a Gen 1 SBC and a carb manifold under the cowl and the hood of your 4th Gen? Do you mind hacking things up to make them fit? Do you have the $$$ and access to tuning for an aftermarket ECU? If the answer to any of these is "no", you are back to an LT1 block.

Then the quesiton is what is your requirement for "driveability"?

In any case, it looks like you need to determine a little more in terms of your requirements, goals and resources, and then pursue the matter on "LT1 Tech". Moving it there.....

 

Thanks for the replies. To clarify: First of all I am on a budget. I'm working part time and going to school full time. I do make decent money for a college kid so I'm not too strapped. I will need to pass CA emissions as this will be my daily driver. I'd be content with 400rwhp.

I've been looking into 383 stroker kits for my LT1 block. I would be able to do the work myself however I don't know exactly what recipe to follow as far as parts go. I'm looking for a rough outline as to what I would need and how much it will end up costing me. This would include any machine work. I've been told it's not a bad idea to get the block x-rayed to check for stress cracks and such. These are the kinds of hidden costs I was unaware of. What else along these lines should I budget for?

Lastly, I need something driveable and California emissions friendly. Please help me plan this out.

 

I recommend that you go the nitrous route......
First of all, start off by finding a decent machine shop to work with. Then, if you want a stroker, go ahead and find a good all-forged rotating assembly. The machine shop should be able to decide if the short block is in good condition or not. After everything is all checked out, get all the machine work done. As far the heads go, I would get the stock LT1 heads ported if you are on a budget. Or you could be the first person to try the new Trickflow heads Then, slap on an emissions friendly cam, like the CC305 or a custom-grind emissions-friendly nitrous cam. Naturally aspirated, you might not make 400rwhp, but with the forged bottom end, you can then spray the heck out of that engine. Plus you can still pass emissions. Good luck.

 

400 rwhp is attainable with your LT1. I really don't see the need to change blocks. Before I read your last post I was going to recommend possibly going LS1, but there is no need.

If you are asking will a 383 LT1 make in excess of 400rwhp, the answer will most likely be yes. The fact that you need to meet emissions makes building this thing more difficult, but it is definantly not impossible.

Just take note what the others have been telling you, if you change blocks, the computer is goign to get angry, therefore needing you to install a new system to work with what you got, or no computer at all (carb'd). Stick with the LT1, it's got PLENTY of potential.

 

Ok, I'll stick with the LT1, port the stock heads and get a mild cam. As GhostZ recommended, Combination Motorsports has some nice looking 383 engine kits. But what about the top end? What will I have to change as far as my valves, springs, pushrods, etc? How much will this cost me? How much will getting my heads ported cost me? I'm trying to do this right while spending as little as possible. Please keep the responses coming.

 

Also, what size injectors should I go with?

 

What about a Nice 406TBI???

540hp & 620TQ@Flywheel emission's leagal $4,500.

It meets our standard's here in wisconsin .

Can't wait till the rest of the car is done I wanna drive it.....

 

I would be more curious to what CA people say.

 

Getting 400rwhp AND being able to pass CA emmisions isn't easy for an NA setup. Something on the order of a 305 cam or an extreme grind with similar timing is near the limit of passing. I would guess that an extreme grind with 224/230 degrees and 114 or more lsa might work in a 383. There are a couple of guys on this board that do very good head work at reasonable prices, Lloyd is one I think, do a search and you should find them. They could probably give you better advice. I don't agree with most of the people on here about the rotating assembly. A good cast steel crank from Scat would work for 400rwhp and cost much less that the trick forged cranks everyone says to use. If you don't spray it or supercharge it you could also look at using some of the better hypereutectic pistons from someone like Keith Black.

I'm building a 383 myself but it is supercharged so I am going at it a bit differently. My cam is very small duration with a lot of lift. On the 383 it will run out of steam by 6000rpm or less but I know I will not have a problem passing CA emmisions and it will have gobs of lowend power. I will be using 42lb injectors and unless I go crazy with the boost they should be plenty big enough.

Good luck.
Tim

 

I have about 2000 miles on my 385 and I also have to pass smog, Which is 1 reason I run a blower in Ca. My cam is 228/236 113 lsa 510/533 . I don't think I'll have any problems passing smog. My motor will spin past 7000 rpm but I don't run it past that, TimChiaretto, You might want to reconsider your 42# injectors, I'm hitting 95% duty cycle at 5700 rpm in 3rd gear on only 5lbs. boost and plan on getting the low Z 72#er's and a converter box.

 

RCF925

Thanks. I guess I will have to go the same route. With my smaller cam I won't be making the same horsepower as you but if I decide to go to 10psi I won't make it with the 42s.

 

So you don't think my 406TBI would pass ca's emission's test's???

 

Most people are making 400+rwhp with just a H/C combo. It shouldnt be hard to achieve with a stroker.