327 vs 283

[Dan Fahey]

Originally Posted by Corvette Guy

Dan,

are you saying 327 runs better with a 1.94/1.50 than with 2.02/1.60 valves ???

In Stock the basic ..929 class cams are right about .400 inch..Not much Lift.
The 2.02/1.60 will not show much performance improvement because the port sizes are near identical. Go with a high lift high rpm SS cam and you can see the difference.

There is a similar battle between the 441 and 492 heads for the 350/255 and 350/290 SBC engines..
There is less that a tenth difference between the head though the Compression is a bit more with the 492's. NHRA lowered the HP but the 290/300 is not as competitive an engine and class difference.

In 2009 spoke with Joe Mondello (rip) at length about SBC and LT1 Iron Heads.
(Read every article he ever wrote on cylinder heads, porting and bought his head porting kit.)

He said the 1.94/1.50 valves are near perfect for stock SBC heads.
Adding the 2.02 intake would reduce low speed flow and low end torque for a 350.
Though the 1.60 exhaust would benefit a SBC head.
For a 383 Stroker the larger intake will get that high speed flow back where you need it.

From his instructions carefully port/chamber/polished a set of LT 1 Irons and used Stock sized high flow valves without using a flow bench. I did use a wetted string..!

Installed them on our PINKS car with a junk yard 350.
The car ran 8 tenths quicker over their modified LT 1 Aluminum Heads they used later.

Another nice benefit of a 327 is the Rod Stroke Ratio.
The heads have the same port size and configuration of the 350.
For some reason the 327 produces near the same HP as a 350.
Mostly because the shorter stroke it and near identical port volume the 327 rev higher to make up some of the lost torque of the 350.

Hope this OVER the Top View helpes ;-)



D