[KingLT1]

Originally Posted by JSH

Here's BTR's Hot cam"
BTR RED HOT CAMSHAFT

221/24X, .619/.617, 113 LSA

INTAKE LOBE LIFT @ TDC: 0.04730

That's a small Gen 4 LS cam. Good cam but not what you need.

Originally Posted by JSH

Both LME and Katech agree that the cam proposed by LME is a race car/motor cam, but that's not mine. I'm going with KaTech's Race Day cam, which has minimal overlap. You saved me from myself, again.

Yeah, you would have been ready to sell the car if going with that CID cam. 24 degrees overlap is not for the faint of heart. And chances are you might of ran out of blower trying to keep up with the RPM that cam wants. And the 24 degrees that the intake and exhaust valve are both open will bleed some boost lowering blower efficiency. Not really what you want to do when your Eddie 2650 is close to its limits already.

Honestly the cam that is in your setup now isn't bad for a 390. The Katech cam will idle even smoother and be stealthier. It only has 3.5 degrees of overlap.

[JSH]

Originally Posted by KingLT1

Honestly the cam that is in your setup now isn't bad for a 390. The Katech cam will idle even smoother and be stealthier. It only has 3.5 degrees of overlap.

I've looked for a cam with a little more overlap than my current 5.5, but haven't found one. LME jumped from 5.5 to 24 degrees due to the new heads, but it's somewhere in between, like 12-14 degrees. LME and probably KaTech will grind it anyway I want.

[JSH]

Originally Posted by KingLT1

Honestly the cam that is in your setup now isn't bad for a 390. The Katech cam will idle even smoother and be stealthier. It only has 3.5 degrees of overlap.

One of the major cam suppliers has suggested:

236/252 Duration @ .050''
120 LSA, 116 ICL (120+4)
.648''/.639'' Lift with 1.8 rockers

Which has 12 degrees overlap, which is a compromise, but I don't know if a cam is worth extra $$$$.

[ZL14ever]

Originally Posted by JSH

One of the major cam suppliers has suggested:

236/252 Duration @ .050''
120 LSA, 116 ICL (120+4)
.648''/.639'' Lift with 1.8 rockers

Which has 12 degrees overlap, which is a compromise, but I don't know if a cam is worth extra $$$$.

This cam has only 4 degrees overlap

[JSH]

Originally Posted by ZL14ever

This cam has only 4 degrees overlap

Another example of my failing memory.

[JSH]

Examining these CID LT4 flow numbers, it is evident that more lift is better. I don't know how much piston clearance I have now.

[JSH]

Heads arrived so we'll start putting it back together next week

[radz28]

GD - THOSE ARE PURDY!!!

[RobZL1]

Originally Posted by radz28

GD - THOSE ARE PURDY!!!

That's exactly what I was thinking. Nothing prettier than a freshly-CNC'd piece of aluminum!

[JSH]

Originally Posted by RobZL1

Nothing prettier than a freshly-CNC'd piece of aluminum!

She's coming back together. CID heads, Eddie, and the new intercooler tank are done. Ordered longer pushrods, headers next week, need 12 gal. of Stay Frosty, and going to take a good look at the rear main seal area to see if I can avoid a 13-hour shop charge.

[RobZL1]

Originally Posted by JSH

She's coming back together. CID heads, Eddie, and the new intercooler tank are done. Ordered longer pushrods, headers next week, need 12 gal. of Stay Frosty, and going to take a good look at the rear main seal area to see if I can avoid a 13-hour shop charge.

Lookin' good! Nice to see it coming together. Good luck with the rear main!

[JSH]

We're doing fluids tomorrow and will crank it up, drive it around, scan it, see if everything's working, such as the WB. See if the intercooler system has any leaks, etc. I'm not going to dyno it now, but rather we'll road tune it and dyno later. I decided to do the rear seal sometime during the winter.

The only new stuff are the heads, push rods, plugs, injectors, and intercooler tank

[2023_ZL1-AUTO]

radz28 is right... Those heads look amazing! Great job on your build and good luck on your first test !

[JSH]

We've got the car back together and tuning is underway. But let's talk a little bit about this rear seal. We've taken a close look at it and there is a little bit of moisture on it, and it looks like there was one drop of oil that was about to drop. But my questions are, when did GM change to such a flimsy LT4 rear? The front seal is much firmer and of course as is the LS rear seal.

I have spoken with LME about the clearances in this engine being greater than stock clearances. I'm assuming that that contributes to additional pressure on the rear seal?

I assume that if a ring was hurt, it's highly probable that it will blow out a new seal