[SD455DJ]

Originally Posted by 67Lemons

As I mentioned above. There are a pair of #62 heads available locally but they have 72cc chambers which would probably be too much compression for the street with my stock pistons in the ‘68 short block?

My current 15’s are supposed to be 75-78cc’s from the factory, will the 72cc heads raise compression too high for pump gas with the stock original pistons in my 1968 400?

Your ’68 #15 heads are listed at 75 cc chambers (10.5 advertised compression) and the ’70 #16 heads are listed as having 78 cc chambers (10.0 advertised compression). My #16’s measured 80 cc’s before resurfacing and 78 cc’s afterwards, right on the advertised chamber size. My 400 is + .030” over, so actually 406 cu. in., with a quench of .040”. The actual calculated static compression is 9.94 to 1. With your std. bore block and factory pistons, probably .020” in-the-hole, your actual compression with your #15 heads would be close to 9.80 with a .039” head gasket (Felpro 1016). Quench would be ok at roughly .060". This would be manageable on 93 octane fuel with a factory style (slow) timing curve and carb jetting slightly on the rich side, along with a good cooling system (temps under 190).

Dennis

[Lee]

Originally Posted by Jay S

Keeping with 1.5s, with no jump in lift against a 068 is the Melling SPC-3 (744). It does not have the dwell over the nose of the old 744 cam, and doesn’t require extra spring pressure over a Melling SPC-7 (068).

Lee on here has the biggest cam I have seen successfully using press in studs, is in a 455. IRC…about .445” lift and 222*@.050 intake, just over .43” lift and 240* ish on the exhaust.

222/242 @ 0.050", .443/.435 valve lift, 116lsa. It has been on a 111icl, but I just changed that to 113 (and installed a converter with a bit more stall). I had the cam custom ground at Bullet.

I have the pressed-in studs, as well as the rest of the stock non-adjustable valvetrain parts. Somebody pointed out that my cam is somewhat similar to a 744, if 1.65's were used on the 744.

FAR from the fastest car I've ever owned, but it still has enough power to be fun to drive, and does it on 87 octane :-)

Dyno graph for when it was on the 111icl. I'll try to dyno again soon, to see what difference the 113icl made.

[67Lemons]

Originally Posted by Lee

222/242 @ 0.050", .443/.435 valve lift, 116lsa. It has been on a 111icl, but I just changed that to 113 (and installed a converter with a bit more stall). I had the cam custom ground at Bullet.

I have the pressed-in studs, as well as the rest of the stock non-adjustable valvetrain parts. Somebody pointed out that my cam is somewhat similar to a 744, if 1.65's were used on the 744.

FAR from the fastest car I've ever owned, but it still has enough power to be fun to drive, and does it on 87 octane :-)

Dyno graph for when it was on the 111icl. I'll try to dyno again soon, to see what difference the 113icl made.

That is a pretty cool build that you obviously put a lot of thought into. What was the reasoning for sticking with the stock valve train & press in studs? A specific class that you race or ?

[Lee]

Originally Posted by 67Lemons

That is a pretty cool build that you obviously put a lot of thought into. What was the reasoning for sticking with the stock valve train & press in studs? A specific class that you race or ?

I was a bit curious about what sort of performance I could get with the non-adjustable valvetrain, and also with a low-compression 87 octane limit.

I've gone 11.2's with flat tappet cam and iron D-ports, 93 octane and streetable. Built a bunch of 9.0-9.5 Dport 455 type motors. I wanted to do something different this time.

It has done better than I expected :-)