LT4 coversion....How much HP gained

[wrd1972]

Just curious, what kind of performance gains can on expect from the LT4 conversion kit. Will it whip an LS1 SS.
Also when doing it is it easier to remove the engin or just do it in the car.
Thanks

[99v6cam]

LT4 keep up with an LS1? Prolly... LT5 definatly but I don't think a conversion to an LT5 from an LT1 is possible.

[Craig 94 TA GT]

With a perfect tune, the LT4 hotcam, LT4 heads and headers, it can be worth up to 425 flywheel hp. No stock LS1 can or will keep up with that. However, if your only goal is to whip an LS1 SS, I would suggest getting a combo from Lloyd Elliott. www.eportworks.com
Any of his packages will outflow stock LT4 heads.

[DJ Taso]

With the money you're going to spend on the conversion, you could of spent it on a 383 package and totally blow the lt4 conversion away.

[Hemogoblin]

I don't know about that but from what I've seen, those Lloyd Elliott kits are very well priced. And to do that install, you do NOT have to (nor should you) remove the engine. To do the 383, that would not only require a new crank and clearanced block, but would obviously require engine removal. And since you're getting into the block, you may as well build up the thing, and do a new cam, heads, etc.... It'll pretty much spiral outta control from there I'd love to do the 383 as well, but with the costs involved, not to mention the work, well, I'll be doing the Lloyd Elliott route, and would suggest the same. Let us know how things turn out

Cheers,
Steve

[Injuneer]

I think the claim of "425+ (flywheel) HP proven" is overstated. If you do a "search", the reasons for this have been explained previously. I think 400-410 (flywheel) HP is very doable, with the correct supporting modifications.

And that is more HP than the early LT5 engines made, and about the same as the highest HP LT5's made, so I wouldn't give the LT5 any advantage over the LT4 "conversion".

A few simple bolt-ons, and the LS1 stays with the LT4 conversion.

[DeWynter]

LT4 keep up with an LS1? Prolly... LT5 definatly but I don't think a conversion to an LT5 from an LT1 is possible.

LT5 is a completly different engine. No swaping of parts there plus at $10000 USD for a used one I think its abit on the pricy side for most people

[fastTa]

Just curious, what kind of performance gains can on expect from the LT4 conversion kit. Will it whip an LS1 SS.
Also when doing it is it easier to remove the engin or just do it in the car.
Thanks

For about the same amount of money you could port your LT1 castings, install larger valves and better springs, port match the intake manifold, install a moderately sized cam, and install a larger TB. This would make significantly more horsepower than just the LT4 conversion alone.

If you just have your heart set on the LT4 conversion just so that you can say so...then by all means do it. However, if it is horspower you seek, go with the above.

[darkz711]

isnt the cost of an LT4 conversion just as expensive as getting a salvaged LS1? If you can beat em, join them?

[redbird94]

there is a much cheaper route like ta said if all your looking to do is eat a LS1 SS or WS6. some 410 gears, short shifter,get some long tube headers BBK run 350 in chrome with y-pipe,cold air intake, run straight thru cats, 3 inch exhaust a good tune and some nasty rubbers and youll stay nice with a LS1 SS.

rear gears installed-figure 500 with labor
headers with y-pipe- 350
cold air kit(SLP)- like 200
good catback(most say Loudmouth)- figure 250-800
good computer tune mail in (pcmforless.com)- like 200
Nitto NT555 radials- like 400 for rears


your total is around 2,400 all said and done. you will not be underimpressed by these mods it will wake up your car, still be completely streetable, good on gas. youll actaully be pushing around 315-350 horsepower with good plugs and tune. on top of that you can throw a nice comp cam in there with like a 510 lift or so the 268 and 280 grinds are nice on these small blocks. thats a easy 30 more rear wheel horsepower running 670 out the door with new lifters, springs, and retainers from ramchargers.com.

good luck let us know what you decide

[redbird94]

well scratch most of that i just say your mod list. you shouldnt be too far behind a LS1 SS, maybe 50 ponies or so at the most

1995 Chevrolet Z28 Convertible, 350ci LT1 6speed, Callaway CAI, Borla SS exhaust, LT4 clutch, 52MM TB, Corvette C6 17" wheels, Cooper 2XS Zeon 275/40/17 tires, Hypertech PP, SS spoiler, cross drilled slotted rotors, LS1 brakes, Hawk brake pads, Zaino protected

well-
Callaway CAI
Borla SS exhaust
LT4 clutch
52MM TB

you want to eat one get a 410 ring and pinion installed that will wake her up. a set of headers, offroad y-pipe, and a 268 or 280 grind comp cam. the 280 lobes nice. thats around 670 with lifters, springs, and retainers then youd need new gaskets.

that will net you a good 60 ponies easy with a nice tune. and save you some nice cash set aside a good 1800 for those mods, plus with that tb you have its gonna open up a huge list of mods that you will new more hp from by getting more air in and out smoother and faster. thats the secret.

now you gotta get that to the ground

that should put you at a easy 350-375 i would say. that will allow you to rip a LS1 SS. traction would be your biggest issue with that. a set of subframes, panard bar, and some new lower control arms would be a nice upgrade. make sure you got some decent rubber and have fun. keep it at the track.