HP Reduction Request

[Alan Nyhus]

Originally Posted by Mike Jones

Thanks, Mark
I thought two 4 barrel`s made it 425HP
Mike

Not in '62...those were 409/409's. The '63-'64 dual quads are 409/425'S.

Denny Ford races a C/S '62 409/409.

[Greg Reimer 7376]

The '62 409 horse and 380 horse engines were exactly the same as all '63 400 horse and 425 horse engines, except for the exhaust manifolds and the chrome parts. The '64 400 and 409 horse engines had a mid year change,actually mid November 63, where a higher lift camshaft was installed, number 3837735, and the heads were 583 castings. The only difference in the 690 head available in 62-mid year 64, and the 583 head was that the valve spring pockets were deeper to accommodate taller springs and more valve lift. The heads and the cam had to go together-putting a .540" or so lift cam in the earlier heads with the shorter installed height springs would coil bind the valve train resulting in rocker arm breakage and flat cams. Still,the horsepower ratings were 400 for the single 4 barrel, and 425 for the dual 4 barrel engine. The 409/425 was not available in '65. the 340 horse and the 400 horse was the last of the 409's, only about 2800 or so total 409 engines were sold in 65 Chevys.