bent1

I have flat top pistons with valve reliefs and running with a MS3 camshaft. Now the heads are Ls6 Prc stage 1. Before I had the heads milled they cc'd them at 62cc. The heads now are milled .035. Is this going to work or did I make a mistake?

poltergeist 02

iTrader: (65)

If the heads were at 62cc and you had them milled .035" more, I think that puts you around a 57-58cc chamber. what are you planning on running for head gaskets? Also how deep are the valve reliefs? How far do the pistons stick out of the bore at tdc?

bent1

I will use the GM stock MLS gaskets and the top of the pistons are flush at the top of cylinder at TDC. I don't have anything calipers here with me now to measure the valve reliefs but may be the picture can give you some idea. Hopefully

outkast6991

iTrader: (34)

Eyeballing and guessing are bad ideas

1BAD98LS1

iTrader: (33)

They look similar to like -2cc reliefs. An MS3 isn't a huge cam but still would be a good idea to check the PTV before running it.

bent1

Ok i measured with a scale and the intake relief is 4mm deep at the deepest point. The top of the pistons have the number 6398f3905 engraved in them. Its a Texas Speed short block 347.

poltergeist 02

iTrader: (65)

If you don't have the propper tools to measure, I would give Texas Speed a call since its their products you are working with. They should be able to give you a good idea of about where you are at in terms of clearances.

bent1

I did call them and ask but they were no help. They said they lost all there records in 2011 and said they couldn't help me. I bought my short block in 2010.

bent1

Somebody has to be running something similar to this set up I would think or at least be familiar with it.

1BAD98LS1

iTrader: (33)

If they are in fact -4cc reliefs that's a good size relief.

Burken01

iTrader: (88)

Exactly.. Check PTV and there's your answer!!

bent1

They are 4mm deep measured with a scale

Burken01

iTrader: (88)

Were not talking about your relief size, you need to measure the distance between your valves to the point where they almost touch your piston inside the relief..

Some people will say just run it, but its good practice and peace of mind to check for yourself. That way you have no doubt...

badazz81z28

iTrader: (6)

The correct answer is to assemble and check PTV clearance. I honestly think you will be fine. If you didn't have valve reliefs, I would be concerned. Since you do, I think you will have enough clearance.

bent1

Thanks all for your input. I will have it back together after my new oil pump comes in on Wednesday.

JakeFusion

iTrader: (7)

Why did you mill it so much? That puts you around a 55-56cc chamber... If it was 62cc before, they were already milled some. Of course, if the motor is zero decked, 56cc is about right and puts you at 11.8:1... just like me with 58cc and flycut pistons with pistons out of the hole .007".

And you can check PtV with playdoh. Put the playdoh in the relief, install the head on the engine with the old stock gasket and turn the crank over by hand. Pull the head, use a razor blade to cut the playdoh in half and then measure the thinnest point. Also check to make sure the radius of the valve didn't contact outside of the relief.

This is not the most sophisticated method, but it'll work for you.

bent1

I will do that and check them after work today. Can I do that without the old gasket? I threw the old ones away already. I guess if they contact I'll have to use a new gasket and recheck.

JakeFusion

iTrader: (7)

Well, you want to compress the gasket best you can to get an accurate measurement. Once you compress a gasket, I prefer not to reuse it. So you could try without a gasket since your block is zero decked and won't have to worry about the piston coming in contact with the head. If you clear with that, you know you are fine + an additional .051".

bent1

I just wanted to say that everything worked and it's running great. In case someone else is thinking of running a similar set up.

Burken01

iTrader: (88)

what did it put down power wise??