Anybody ever check one of these things? I got 177.5 on chambers, & Dome volume around 62.2 CC?????? 7.95:1 Compression?

Only thing I've done was VJ, & blended seats into chambers..... But that did'nt kill point of compression... looks to me, I'm going to have to mill heads around .080" to get it up to 9:1 where it is advertised?

What cam and how much overlap??

i'm not surprised.

Well I dunno what it had in it from MP, some small Hyd FT. I'm putting a mild roller in it, 254/258 on 108 LSA. I don't have cam card in front of me, but lift is in the .650" range.

I finished heads up @ beginning of week, OOB they went like 303 cfm? Exhaust was just horrifficly bad 170's? Don't remember exactly.... I did real basic work to them & bumped into the low 350's/230's with no tube. This is just supposed to be mid/low 11 sec motor in a '70 HemiCuda, nothing special.... Rod bearing clearance was @ .0008"... yes I wrote that correctly. Mains were .0013"-.0014". Had to take crank .010/.010 to fix that mess. Actually more like .011"/.011" but.... I got it it set around .0031" Mains, .0027" rods now with 3/4 Groove Federal mains & set of H Clevites on rods to replace the factory stuff.

Was just surpirsed to see compression was as low as it was. I've never CC'd a Hemi head before, I don't know if 117 is high or what. They have fully machined chambers in them so, not alot of room for error there.... Piston looks like a Wiseco? This is an older Cummins built 426 Crate not a newer Stanton motor BTW.

Check the deck hight. Many of those block are tall. I have measured a few engines myself and found them to be in the 8.2+/- range.

Im not surprised at all.
Can those heads be milled that much? I figure with that much cutting the valve seat would be hanging in the chamber or physically be cut into at that point.
Here is a pic of probably the same heads if its a new Crate engine. These are cast by Edelbrock BTW

This is an older motor W/ Iron MP heads on it. I can cut them to edge of 45* intake seat if need be.... Just sucks I have to cut them that much as the manifold will have to follow suit... driving costs up.

The SB 360 Crate motors always seemed to be much closer to advertised compression, that's why I was surprised to see it so far off.

The best AC/Cummins one I've ever heard of had 8.7:1 and it was a rarity...most of the ones that came out of Cummins were at least half a point lower.

The AE/Stanton ones generally come much closer to hitting advertised compression, but the catalogs were changed recently and now the advertised compression is 8.7:1, so the target is much more realistic with the pistons being used.