SS#2906

iTrader: (53)

As much research and searching I have done, I cannot seem to find solid answers. I have a set of PRC heads from TSP and I am trying to do my home work before I start the install

I currently have a Cam Motion 239/244 .61193 intake lift and .61267 exhaust lift and I am hoping to not have to flycut the pistons.

In searching I found alot of people running MS3 cams and some even MS4 without flycutting.

MS3= 237/242 .603/.609 lift clears these heads
MS4= 239/242 .649/.609 lift has cleared for some, others not

Can I use a thicker gasket possibly to help out?

Cold06

iTrader: (9)

Just depends but you need to check ptvc to be safe but that cam is close to mine and I did have to fly cut them....

johnster

iTrader: (27)

ur more then likely going to have to flycut, those heads come from tsp at 62cc the ms3 is the biggest u can go with out fly cuting, and thats with stock gasket!

SOMbitch

iTrader: (8)

Everybody thinks they are 62cc but they are 63cc+ after the bowl work

LSA and advance will also affect PTV and the OP never stated that. It might or might not clear but it would be so close I wouldn't risk it. It could easily come back to bite you in the a$$ later...

As far as I know the GM MLS at .052 compressed is the thickest off the shelf gasket and besides I would get a slightly smaller cam before I would lower compression, Unmilled those heads will yield about 10.7-1 SCR.

SS#2906

iTrader: (53)

LSA is 114 and the cam card says Camshaft Data= 4 Crank Degree, is this what the advance would be?

I'm also running a 175 shot, so flycutting worries me. I think I'd rather swap the cam to an MS3 before I flycut.

Sales2@Texas-speed

iTrader: (5)

Fixed that for ya

OP: You really need to check clearance on that one. It's a very aggressive camshaft and without flycutting the pistons, it's going to be tight enough that you want to check it!

cranny

How does one go about checking ptvc and what tools are needed? I see it mentioned a lot but never see an explanation how to go about doing it.

mark21742

1st, only use a normal 1/2" drive ratchet...do not use a breaker bar....if you are turning the engine over and you feel ANYthing more than normal friction stop immediately.....this might be a valve touching and pushing on the piston.

Take a small piece of modeling clay ( about the size of a gum ball) smash it pretty much flat on piston covering the area where the valves come down toward the pistons....

Bolt the head down with the gasket.

Turn engine over atleast twice by hand with your 1/2"ratchet

Pull your head back off

Measure the depth of the clay where the valves left their imprint.

You need a minimum of .080" intake and .100" exhaust

If you have less than either you need to flycut enough to get these clearances

SOMbitch

iTrader: (8)

Thanks Matt I just misspoke.

Mine were cc'ed and flowed after they came off the car by a buddy who works at a machine shop just because he wanted to do it for the heck of it. The chamber work you guys do basically opens them up to optimize the larger 3.898 bore it looks like....

Sales2@Texas-speed

iTrader: (5)

Yes sir, that is correct

BrntWS6

iTrader: (7)

Yeah...you definately don't wanna go through taking the head off and fixing that. I'm going through this right now because I rolled over a valve on one cylinder.