How much power can be expected from switching from the stock lt1 headers to LT4 heads? Only switching heads, not cam or anything.

 

Maybe 5 HP. Without changing the cam there isn't much point. Putting on the LT4 heads (and required intake manifold) would not be a worthwhile investment whatsoever.

 

Alright thanks for the help

 

My fiance ran high 12s with LT4 heads/intake, WS6 intake, 1.6 rockers,stock cam, shorties, 3200 stall, 3.73s and a cutout on street tires. Full race weight. And she hung with H/C LS1 cars all day.

 

High 12's and hanging with h/c ls1's? And those times are about on par with what a bolt-on lt1 would run.

 

Lt4 heads would require an LT4 intake as well, as the lt1 intake does not mate up to the lt4 heads. A quality port and polish job on the stocker LT1's would be a better and cheaper investment. Check out AI (advanced induction) and LE (Lloyd Elliot packages from Elliot Portworks)...2 of the best porters in the LT1 world, it's amazing what bang they can give you for your dollar by reworking stock equipment.

 

True, but she ran shorties and a cutout with stock cats. Imagine adding LTs to that. So they are worth something. And yes we have 3 friends with H/C LS1s making over 400 and she was right there with them from a roll or dig

 

Maybe so but not running high 12's. Bolt on LT1's are capable of that.

 

She has the timeslip to prove it

 

All I'm saying is that if a full bolt on car can do what she did with shorties and a cutout on that topend, add on the power from LTs and knock more time off. But OP unless you find a good deal on them look for ported stockers. They will net you more gain than unported LT4 heads will

 

I was hoping you were mistaken on the 12 second timeslip. Those LS1 cars should be running 11's minimum unless you all are running at elevation or in the middle of the desert.

 

She ran them on the street/freeway in so cal. 2 are H/C bolt on 6 speeds with 4.10s and 1 is 3.23 geared

 

This argument is retarded.

 

not worth it

 

I had a guy selling Lt4 heads and intake for 400 so I was just wondering. I plan on getting a cam later.

 

if you are willing to spend 400 dollars for 5 horsepower I have an airfoil I will sell you haha You pick up the paypal fees and i will throw in a TB bypass j/k save that money to get your heads ported and the stock intake actually flows pretty good the way the general made it but it all depends on what kind of power goals you have.

 

I'de buy them just to throw them up on ebay and easily double your $$.

 

Stock LT1 heads= 212/215cfm. Stock LT4 heads= 230/243cfm. 10cfm= about 10hp, so the stock LT4 heads would be about a 15 hp gain with your factory cam. If you have a cam with about .500" lift or better the stock LT4 heads can be worth up to 30hp over the stock LT1 heads.

 

It may not match perfectly, but it will work.

 

right? you could prolly get $400 for just the intake
for $400 you can't really go wrong man! just make sure ther actually LT4's