tmirisola

Knowing the LT4 has 30 more HP than the LT1 how was this achieved? I would assume the blocks are the same.

hockeyhead019

I believe it has a different cam profile and different heads... I'm sure somebody who actually knows will chime in soon tho haha

ColaBear

This link should help with your quest:
http://www.grandsportregistry.com/lt1vslt4.htm

tmirisola

Awesome information ColaBear. Thank You. Looks like the LT4 was built for higher top end RPM with the torque staying the same as the LT1.

Great reading :-)

Now, what bolt on products are there to increase the LT1's HP & how much can be easily be gained.

Paul Workman

Speed cost money. How fast do you want to go?

CHEAP - FAST - RELIABLE... Pick any two!

There is no easy way for this (former) SBC builder to answer that question..because "how much" and "easily gained" have a different meaning to everyone that asks that question.

But, for example, 425 HP at the crank for a second gen. LT1 can be had for around $2.200 using the HOT CAM formula, on the cheap (e.g., no new bearings, pistons, rings, repairs or extra machining, etc).

I've ground up enough SBCs to know that if you don't start with a goal and lay the groundwork down first (read: use all the right stuff), the project will be short(er) lived than you might want. Before you'd want to, you might find yourself going back into the motor to "do it right". Oh, and keep your AAA membership up to date. Just sayin...

1993C4LT1

1.6 roller rockers
longtube headers

Yes, I know you can install a cam for less, if you do it yourself, but at least with those two mods, you don't have to go deep into the engine.

v8vette84

I agree with the headers, but not with the 1.6rr's. Roller rockers basically net you no measurable HP increase. They aren't too expensive but you will not notice any difference in power. Better air filter/intake would be a better choice than rr's.

Search the forum, TONS AND TONS of info regarding hopping up LT1's. Hell, search it on google, there is a ludicrous amount of info out there. Good luck!

96GS#007

His point is about the ratio. The stock LT1 has 1.5 rockers. Moving to 1.6 consistently nets 15hp at the rear wheels. It's like swapping in a slightly larger (more lift) cam. As for the roller element...I agree, if someone swapped in 1.5 full roller rockers or roller tip rockers, the gain would be minimal at best.

hockeyhead019

this is a decent article detailing mods and improvements based on those mods for an LT1 engine

Super Chevy LT1 Mods Part 2

Goldcylon

LT4 is a fine engine. Paired with the ZF-6 its a pretty spirited C4 straight from the factory. With a few more mods even more so.

v8vette84

I'm sorry but going from 1.5rr's to 1.6rr's is not going to gain you 15rwhp. The small amount of lift a 1.6rr adds will not equate to 15rwhp. Most of the hp gained from a cam is in the duration not the lift. I even spoke to Lloyd Elliot about this in the past.

ovrebo1

I think for <$150 for some eBay roller rockers, its worth it

SJW

I'd swap to a higher-ratio gearset in the Dana before I did any mods to the engine. If that doesn't satisfy, then consider engine mods, but understand the can of worms you're potentially opening up if you wade into those waters.

Live well,

SJW

AgentEran

Gears and LT Headers..

v8vette84

pologreen1

If you are willing to mod, don't let the lt4 be your goal. Good cam, heads, and intake porting will get you 425hp

DrDyno

I have to differ with you. Not only do you get a 7% boost in lift but you also get a 7% increase in duration. I installed Scorpion 1.6 roller rockers in my '96 LT1 along with LT4 valve springs. I'm not going to make any outrageous claims based upon my SOTP dyno but the car does feel more responsive and appears to get to 6K RPM before the electronics can stop it.

HOWEVER... there is a forum member with an LT1 who dynoed the car before and after installing just the 1.6 roller rockers (he didn't say if he changed the valve springs or not so I think we can assume he did not).

His dyno tests indicated a 10 HP gain at the rear wheels with the rocker arm change. Following is a link. His post is #6.

https://www.corvetteforum.com/forums...rs-in-lt1.html

v8vette84

I have 1.6rr's myself as I like that they are bearing rockers not the stupid sliding steel ones. (Less friction) Plus they are built A LOT better than the oem stamped rockers.

Also I'm pretty sure going from 1.5 to 1.6 roller rockers does not increase duration. How could they? Do they magically make the cam lobe bigger? No, they just get the valve to the higher lift faster and back to the seat faster.

If you change just the rockers the lifter is still going to ride on the same cam lobe and the only difference is how far the valve opens. Basically the 1.6 rockers are opening and closing the valve faster (netting no gain in duration), the valve will still open and close at the same time as the 1.5 rockers.

Also a 10hp increase could have easily been ANY other factor. Usually when ppl do a dyno pull 3 times all 3 reading are quite a bit different.

I would like to know exactly how the 1.6rr's increase duration? If I'm wrong I would like to be corrected. I just don't see how it's possible.

DrDyno

Yup... it's magic!

Nope... it's not. I misspoke. Thanks for pointing out the error.

However, I think it's silly of you to stick to your "no HP gain" based upon how you feel about it when another Forum member says dyno results show otherwise.

v8vette84

I assume roller rockers do add some hp but I don't feel like they add enough to make much of a difference on a stock engine. I'm not arguing their value as it's not bad at all. ($150-300 for a decent set) The thread you linked the guy said he got a 10whp gain and again that could be any number of differences besides the rockers. For example if you run a "300hp" car on the dyno the car will not make exactly 300hp every run. One might be 280 then the next 292 then the last 285. I'm not saying no gain at all, I'm saying I think you get much less of a gain than what people seem to think. Hell I have seen ppl claim 40whp gain on rockers alone. That's insane to me.

I agree with a gain but not with a huge gain. Same idea as a CAI, everyone claims they give like 20-40hp at the wheels but it just doesn't make sense. Most "cold air" intakes suck hot air anyways, hence my skepticism.

Hey regardless of what I think if he got a 10whp gain with just a rocker swap then good for him. That's pretty good.