LT4 top end

Was buying "go fast" parts for family and friends today and got into a discussion with the owner of the establishment about a "LT-4 conversion kit" that he would gladly sell me for....... wait for it........ $3200!!

According to him, he has a 96 F-body LT-1 with the LT-4 top end (heads, cam,intake and fuel rails) he has dino'd 460HP and 475tq to the wheels!!

Anyone have experience with this? I just can't see replacing the top end and gaining 200HP and 145tq with just bolt-ons and a computer tune. Hell, I can pick up used parts and have them machined for less.

can't you buy LE heads/cam/converter/injectors/programming for less than $3200?

Never even considered the process, let alone the cost. Just curious if this is a viable option.

The HP is HIGHLY exaggerated!!

To get that kind of HP you would need a 383 and much more cam than the Hot Cam. With the LT4 heads, intake, hot cam, and 1.6 roller rockers you would be lucky to get 60 hp additional. The valve springs in the kit are useless at best.

My heads on my Impala flow better than the LT4, I have better springs, larger cam, etc. I only put down 300 hp and 300 ftlbs at Carlisle. I little light for my set up. CC 503 cam, beehive springs, stock bottom end. Still working the bugs out, but I expect 450 hp at the flywheel. Less 20% at the rear wheels. So about 340 is what I should have.

I originally had that cam (Hot Cam) and ported heads in my car and put 297/306 on another dyno. Those numbers were about right for the LT4 conversion.

His numbers make NO sense..............

Save your money. I've seen a complete LT4 kit on ebay for $1700.

no moa wrote:

Save your money. I've seen a complete LT4 kit on ebay for $1700.

I've seen them too. Question is, what kind of gains would I see and is it worth the time and effort. I would also get used parts and have them machined to save on cash.

Or would I be better off just replacing the rockers with 1:6, and replacing the springs.....

Krzdimond wrote:

no moa wrote:

Save your money. I've seen a complete LT4 kit on ebay for $1700.

I've seen them too. Question is, what kind of gains would I see and is it worth the time and effort. I would also get used parts and have them machined to save on cash.

Or would I be better off just replacing the rockers with 1:6, and replacing the springs.....

1.6 rr would not fit on my car, but when I put them alone on my car I did not see a whole lot of difference. Yep the only cast heads I have ever seen that were not machined enough from the factory to make them work. The best way to go is a set of Loyd Elliott or Advanced Induction heads, cam, pushrods and a set of 1.6 Ultra Pro Mag roller rockers.

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Generally a good local porter can do a good job as well. This is great reference material..... [You must be registered and logged in to see this link.]

Tim

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Lolyd Elliott set up............ for sale and Roller Rocker we discussed.

Tim, after our discussion, I have decided that it would be in my best interest to start with gears as I pull a 3500# trailer 80% of the time. Looking into the 3:73 option and will see how that goes before I dump big bucks into areas that don't need changing.


Thanks for the advice.

Glad I could help............