Heads are at the machine shop now getting .050 milled off, the intake side as needed, and while they are off the exhaust side is getting evened up. Here we go!
Heads are back and all nice and milled. Haven't been cc'd yet but I will get to that. They are back for mock up for the intake side, and I found that all bolt holes are still centered and I am unable to fit a feeler gauge between the head and intake. I mocked it up using a head gasket and no intake gasket. Is this good or do I need anything else?
Absolutely nothing wrong with what you've done so far, I just prefer to deck the block to bring the piston up to near flush with the deck. Doing this does good things for efficiency, and power. Buick seemed to like to sink the piston pretty far in the hole. My block and piston combo put the piston .055 in the hole, I had my block decked .050 and my heads cut .030 I'd be a bit leary cutting the heads more than .040
Ok lesson for next round. If there is a next time then I'll focus on the block side before its together. But for now this is how I'm going along since its already cut. Does there need to be any space between the intake and the head for a composite style gasket?
No you should be fine. As long as the intake fits nice without a gasket it will fit well with a gasket.
Heads came back today... $235 to have .050 shaved off, the exhaust & intake milled, and cc'd .050 off gave me a combustion chamber of 43cc. I was standing next to the builder and verified that info. I was planning on using the .020 gasket but that bumped my static compression to 10.9767:1. So I am thinking that is a bit to high. Enter in a TA .040 gasket and 10.34:1 static and 7.55 dynamic So I am thinking the thicker gasket is going to be a better route and stick with 10.3:1. Sound good?
7.55:1 DCR is a safer place (vs detonation) and will still net good performance. You can adjust camshaft install point up or down to compensate depending on where you desire your power band and compression ratio. I have heard DCR's up to 8.5:1 are still within the safe zone (with 8.25:1 being preferred), though those are for engines with larger combustion chambers and quench zones. For the Buick 350's smaller combustion chamber and open design (no quench), 8:1 should be close to optimal, while anything over 7.5:1 still being good. With a little less than 8:1 DCR (say 7.5:1 to 7.75:1), you could pretty much get away with any premium pump gas you came across at any given elevation or atmospheric conditions with proper timing. My 2c--get second or third opinions. Gary
Hey Gary! Pump gas is a top priority, your additional information on this subject is very much appreciated and educational!
Justin, Can you post a photo of your head with the gasket laid on it. Would like to see how much space there is from the gasket edge to the chamber edge.
Sure thing, once the new gasket arrives I'll get a picture up. I imagine it will be some time mid next week.
Justin, Back in the late 70's I did a 1973 Buick 350 by milling the heads .060. I too milled the intake side of the head instead of milling the intake. Strange as it may seem I was even able to use the stock length push rods with no ill effects. I would not use adjustable push rod unless it is absolutely necessary. I think the cam was 284 duration and 484 lift if I remember right. It was ground with the same base circle and it worked. I guess the lifters had enough room to move that much but it all worked without changing the pushrods. The only thing I did different was I also installed 1970 10.25-1 pistons. Even with the smaller dish I had no valve clearance problems. I don't remember how far they were in the hole but most '73s sit about .060-.080 in the hole and the valves never touched the pistons. Good luck with your project. I think you will see a big increase in low end torque with the compression increase. You cam will be happier. As for pump gas...I was able to get 98 octane back then and it was enough. That combo would never run on 93 octane today. David
