Through my research of suppliers and even with some of the great deals from members on here, mod costs for the LT1s are substancially higher then sb carbureted mods. Cost wise to get to 330-350rwhp, seems one could get there for half the cost with the carbureted set up. Anyone done this swap, if so, what benefits have been seen and what negatives have you run into?

 

well there was infinite development for the sbc, and the parts are cheaper since there are so many of them. The drawback is that you lose the adjustability and mileage of the injected engine, and maybe your instrumentation unless you go with a sbc that you set up with an aftermarket efi setup and then tune it correctly. You could make a lot of power with a sbc but lose driveability that efi offers if you went with a carb. As always, enough money would get you where you want to be regardless of what path you take.

 

Thanks Kevin. Budget is a large part of decission, both for initial build up and down the road costs. "driveability" as in what aspects do you mean?

 

Well for instance when you have a computer controlled ignition, you can tell it to retard for starting then advance for idle and completely taylor the cruising and wot ignition curves based on throttle posiution, temperature, etc, but for a distributor, you are stuck with initial advance, mechanical advance, and vacuum advance. Then with fuel, you can adjust the injectors to do whatever you want for starting, hot or cold weather, altitude adjustment, enrichment and closed loop crusing control for mileage, but with a carb it is all mechanical and won't adjust for barometric changes or altitude, you will need a choke for cold start and those don't stay adjusted because they wear. They will just run rich or lean if things aren't perfect.

Anyhow, back to your original question, 350+ rwhp is pretty easy with a LT1. For one thing, you aren't starting with a blank slate, you already have LT1 parts. I'd say get your basics like cold air intake and good exhaust, then get the heads ported and a good cam and you will be where you want to be for way less cost than replacing everything like your engine, heads, and buying a carb, distributor and stuff. I'm not sure what you have in mind.

 

I guess I disagree with the original premise. Twice as much $ to get to 330 at the wheels? It wouldn't take more than mildly ported heads and a mild cam. You'd have to both to a standard SBC. Porting might cost more on the LT heads but not much. The cam would be the same cost.

You can overcome the issues of going away from a PCM controlled engine....but it'll be a pain. IMHO it isn't worth it unless you want huge power and even then you can get there with efi....

 

Not to mention what would you do about accessories, and the distributor clearance with a rear mount distributor in one of these f-bodies is worse than bad.

 

I'm trying to decide which engine for my 73 Z. I have a 355 w/ TFS heads, needs to be gone through, which would include a roller cam & a 3.75 crank. Or I have my old 94 LT1 w/a carb & MSD distributor I already have. Would also be gone through, w/a cam at the very least. I briefly toyed with the idea of putting the carbed LT1 into the 94, but I'd have to cut an access hole in the firewall to get to the distributor. When it comes right down to it, the benefits of FI are pretty hard to beat.

 

I really like the LT1 and feel it is discarded way too quickly by those looking for performance BUT.........

IMO I would not go through the trouble of retrofitting an injected LT1 into an older carbed car. If I were going to go through that trouble I would skip right to the LS motors. 5.3s are so common and cheap, 6.0s only cost a little more.. Yes the car engines are pricey but then a LOT of LS1 have been swapped out for 6.0l because the bigger bore allows for better heads.

If a car has an LT1 I say keep it LT1, but otherwise the LS stuff is so nice it should be strongly considered.

 

A carb swap is not cost effective for only 330whp...a healthy cam swap to achieve ~330whp will cost far LESS than a carb swap.

 

The LT is reversed cooled... Providing higher compression at lower operating temps, providing more torque with much higher threshold for pre-ignition/knock on pump gas. All of which improves with the superior a/f performance of EFI, its just a superior production production platform; as the LS is to the LT.