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Now I have a question on LT4 springs @ install height of 1.780 the seat pressure is 101 pounds. What would the
seat pressure be at install height of 1.750?
In other words, what should the seat pressure be at a 0.030" lower installed height?
The LT4 spring is a relatively LIGHT duty spring. Another .030" might increase seat pressure to 110 lbs, certainly no more than 115 lbs. Even if it was 120 lbs this would be totally acceptable using the stock roller lifters with approximately 'one full turn' of preload.
Yes, I agree. The LT4 spring is at its absolute limit at the .525" lift of the HOTcam (when installed at 1.780"). Anything over .500" lift I would recommend a better aftermarket spring.
Don't even **** around with the LT4 springs. At first I thought they'd be OK but after many discussions with 500hp and others on the forum they're pretty mild and BARELY up to the job with the Hot Cam.
Get these from crane , more seat pressure and rate at stock installed height (but not too much) and they fit better than the stock LT4 springs. Also you can use all your stock spring hardware.
Here's how they fit, I just got done installing them a while back. BTW, I've made a ton of 6500 shifts so far in my LT4 car with the stock spring hardware without a lick of trouble.
Ok that's what I get for posting after being up for 24+ hours. Slalom4me is correct I meant what would the pressure be at 1.750? This is not a LT4 engine or even a roller lifter engine, my cam should have springs with 114 seat pressure and the lift is 467/494 I think the LT4 springs would be a better choice than my current springs + I already have them.
Dave
If you're using a cam with near .500" lift or more, don't do it.
Originally Posted by 500hp
Yes, I agree. The LT4 spring is at its absolute limit at the .525" lift of
the HOTcam (when installed at 1.780"). Anything over .500" lift I would
recommend a better aftermarket spring.
Opel, I don't have any knowledge about the spring and defer to what
these guys say.
What I ask is that you consider how much money you are looking at
for a spring that is more compatible and whatever loss there might be
on selling the LT4 set versus the cost of the consequences of sticking
with the LT4's and having an issue.
How much margin will there be before coil bind occurs?
Ok that's what I get for posting after being up for 24+ hours. Slalom4me is correct I meant what would the pressure be at 1.750? This is not a LT4 engine or even a roller lifter engine, my cam should have springs with 114 seat pressure and the lift is 467/494 I think the LT4 springs would be a better choice than my current springs + I already have them.
Dave
The LT4 springs will work for you. Is that .494 spec with your rockers? You could use a bit more seat pressure but it's acceptable.
Originally Posted by Slalom4me
How much margin will there be before coil bind occurs?
With 1.5 Rockers...
Your installed height. 1.750
Coil bound completely. -1.1875
Gross max lift. .5625
Your max lift. .494
Margin. .0685
With 1.6 Rockers...
Your installed height. 1.750
Coil bound completely. -1.1875
Gross max lift. .5625
Your lift. .527
Margin. .0355
Stick with 1.5 rockers to provide the .494 lift, at .527 lift you're getting into a danger zone.