lt4 heads
lt4 heads I can pick up a set of lt4 heads for $500. They supposedly have been gone through and have new valves, performance valve guides, along with hardened seats with provision for oversize intake and exhaust valves and a clean up mill was done. How can I know for sure if they are good are not? And is $500 a good price for these heads.
That's what I am thinking; I am going to ask for the part number and if I can have them checked out before I pay. I was going to stay away from lt4 stuff but I think $500 is a good price.
The valves are the best part of the LT4 heads. If someone blindly replaced those I would be highly suspect of all the other work.
To be looking at replacing valves in LT4 heads they would need to be heavily reworked so I will go out on a limb and say they got replaced out of ignorance.
The stock LT4 valves are hollow intake sodium filled exhaust, nice light weight stuff.
Look at post number 6. https://ls1tech.com/forums/lt1-lt4-m...1-intakes.html
I would not bother with LT4 heads, if I got them free I would sell them, I actually look for results though and put little faith in bench racing.
To be looking at replacing valves in LT4 heads they would need to be heavily reworked so I will go out on a limb and say they got replaced out of ignorance.
The stock LT4 valves are hollow intake sodium filled exhaust, nice light weight stuff.
Look at post number 6. https://ls1tech.com/forums/lt1-lt4-m...1-intakes.html
I would not bother with LT4 heads, if I got them free I would sell them, I actually look for results though and put little faith in bench racing.
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Verdad Gallardo Go up to my first post. I offered a link to where someone who is a very top level LT1 tuner and successful LT4 head user says not to use them on a 350 held to the stock pcm's limits.
He uses them on a solid roller stroker going to nearly 8000rpm, it is a different beast than the OP here is talking about and Ed is smart enough to know the difference unlike most of the guys replying to this thread.
Here in the real world properly ported LT1 heads actually work better for most street and street/strip builds, once you look at even pure race results I am unconvinced the LT4s are worthwhile.
Having already been halfassed ported is IMO another negative, what happens when material was already hogged out where the next porter didn't want it removed?
I know I don't agree with conventional wisdom but then again to get a street Caprice to run mid 11s NA you have to do things actually right rather than popular, they are different things.
He uses them on a solid roller stroker going to nearly 8000rpm, it is a different beast than the OP here is talking about and Ed is smart enough to know the difference unlike most of the guys replying to this thread.
Here in the real world properly ported LT1 heads actually work better for most street and street/strip builds, once you look at even pure race results I am unconvinced the LT4s are worthwhile.
Having already been halfassed ported is IMO another negative, what happens when material was already hogged out where the next porter didn't want it removed?
I know I don't agree with conventional wisdom but then again to get a street Caprice to run mid 11s NA you have to do things actually right rather than popular, they are different things.
I think I will end up with some lt1 heads from LE; most likely the le1 heads. If any one in CA wants to check them out, this is the link to the lt4 heads. http://losangeles.craigslist.org/sfv...163450423.html
Yes they will always outflow LT1 heads fully ported. But as stated a 350/355 really cant take advantage of it
The big difference is of course the valves but also as stated:
The big difference in the heads is the intake and exhaust ports. Both are larger with bigger radius bends. The "short side" radius of the LT4's exhaust port in particular has been increased to reduce back pressure at higher RPM,s. A throat cut just past the exhaust valve seat also opens up the exhaust port. (Unshrouding valve). The Intake port volume has increasd by 25cc. Increased from 170cc on the LT1 to 195cc for the LT4. The flow through the heads have been increased from 212CFM (Cubic feet per minute) @ 28" (711mm) (LT1) to 240CFM (LT4).
Mine, forced inducted with Ported LT4's, 648 RWHP on the pump and 722 RWHP on the fast gas..I think they are pretty good..But as said probably with a milder build they might be too much? Don't know...The LT4 Vette isnt that radical at all..
The big difference in the heads is the intake and exhaust ports. Both are larger with bigger radius bends. The "short side" radius of the LT4's exhaust port in particular has been increased to reduce back pressure at higher RPM,s. A throat cut just past the exhaust valve seat also opens up the exhaust port. (Unshrouding valve). The Intake port volume has increasd by 25cc. Increased from 170cc on the LT1 to 195cc for the LT4. The flow through the heads have been increased from 212CFM (Cubic feet per minute) @ 28" (711mm) (LT1) to 240CFM (LT4).
Mine, forced inducted with Ported LT4's, 648 RWHP on the pump and 722 RWHP on the fast gas..I think they are pretty good..But as said probably with a milder build they might be too much? Don't know...The LT4 Vette isnt that radical at all..
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Hmmm, I might be on the prowl for some unmolested Lt4 heads, considering they have similar port volumes to LE1 heads, I want to do them to be different, but I might just do LE heads if I find them cheap enough.
I have LE ported lt4 heads and intake and couldnt be more satisfied. theyre on my 355 but im building a 383 solid roller in the near future and they will be going on that as well. 