Streetmaster to Airgap
Is it fair to say that that 125 cc intake port head was only down 20 cfm on that 160 cc port to only show a 40 HP difference?
Yes...... and no.
22cfm difference.....@10”.
100cfm vs 122cfm
These were oval track motors built to fit a specific set of rules.
Mopars could run as big as 318” +.030.
Stock stroke, 10:1cr, stock type pistons only, stock rods, stock cranks, stock non-HP heads, no head porting, factory iron 2bbl intake manifold, with adapter and a 4412 Holley carb.
Any flat tappet cam, roller rockers okay, headers.
The valve size rule was 1.88/1.50.
The previous year they had put 1.88’s in one set of the 302’s they were running, and felt that was a minor improvement over the 1.78’s.
I took that set and did some tweaking to the bowls of that set to improve the form in the bowl with the bigger valve.
The 596’s got ex seats installed to facilitate the 1.50 valves.
The previous year(built by someone else) the motors made around 275hp.
When I built the first motor it made 293hp with the 302’s.
Just like they do it on Enginemasters TV, we swapped to the 596’s right on the dyno.
The motor made 330hp+ with the 596’s.
At the faster tracks, with the car really hooked up, they would turn right about 7k and the end of the straights.