Exhaust

[Bent77]

When I was putting my engine together, I did not research the Offenhauser manifold, didn't know anything about it really. My original heads were so small they belonged on a lawn mower. Went with 2.02 World Products Torquer heads, Comp Cams 4x4 cam, full roller rockers for longevity, +3 qt Moroso pan with crank scraper and windage tray for additional cooling and maybe a bit of HP on the top end, true dual exhaust, rebuild Quadrajet and Jegs dual plane intake. So not far what you prescribe. Stock pistons with trued up con rods and a reconditioned crank. Con rods were a bit egg shaped so I had them trued up for 80$. Hopefully I can have my Corvette manifolds on and exhaust done before the end of Jan. Thats about my last upgrade unless I go full roller cam, but that's a chunk of change to convert over.

Always looking for other performance upgrades and ideas.

Roller cam is a big boost, but having a factory roller block is nice

 

[nitro_rat]

When I was putting my engine together, I did not research the Offenhauser manifold, didn't know anything about it really. My original heads were so small they belonged on a lawn mower. Went with 2.02 World Products Torquer heads, Comp Cams 4x4 cam, full roller rockers for longevity, +3 qt Moroso pan with crank scraper and windage tray for additional cooling and maybe a bit of HP on the top end, true dual exhaust, rebuild Quadrajet and Jegs dual plane intake. So not far what you prescribe. Stock pistons with trued up con rods and a reconditioned crank. Con rods were a bit egg shaped so I had them trued up for 80$. Hopefully I can have my Corvette manifolds on and exhaust done before the end of Jan. Thats about my last upgrade unless I go full roller cam, but that's a chunk of change to convert over.

Always looking for other performance upgrades and ideas.

The Offy is an oddball, maybe no longer produced, Summit Racing still has a listing for it but it's $650 or so. The primary and secondary runners are separated, this keeps velocity up, mixture in suspension, and builds torque.



A 1.94/1.50 valve head is better for torque production, the 2.02/1.60's are for mid-high lift flow, you'll never get to the RPM range where the bigger valves are useful in a towing/torque motor. The bigger valves sometimes don't flow as well at low lift due to shrouding. It's hard to tell exactly without flow bench numbers.

Oil control is always helpful in reducing parasitic losses and also keeping oil temps in check.

I don't build any more SBC's that aren't on a late model roller block, there are just too many of them out there too cheap to invest in the older casings. Roller cams are such a big deal with the current oils that are available. A few oil changes with the special racing high ZDDP oils that are necessary for a flat tappet cam to live will buy a good core roller 350 motor!