i can't help it

[RapidRide2]

i cannot help this oxymoron,,, i am going to be rebuilding a stock 454 in my 79 silverado.. i have some 049 and 781 heads i want as much performance as i can get without sacrificing mileage (or lack of) How much would installing larger valves in the mentioned heads affect mileage,,,, i would probably run a 2.19x1.88??? AND A LITTLE 260 ISH DURATION CAM,, HEADERS,, AND DUAL PLANE. THANKS

[1FaastC10]

more air in + more air out = more power. more power (within reason) = better milage. as long as you're leaving everything else close to stock, i dont see how it would hurt.

[GMC1tondually4dr]

....DO IT!.......

I am building a 496/505 BBC for towing.

Using the 781 heads, just pocket port 1" behind the valves. Put in 2.19/1.88 valves with a 30* back cut on the intake and a radius on the exhaust.

Do not open up the intake, just clean the casting flash. Same with the exhaust. (there are some things that you can do to get more out of the exhaust,but it is too complicated to explain here)

This will keep the velocity up in the ports.

The larger valves let more air past at the same lift as the smaller valves.

The engine is just an air pump, air in, make energy, air out, ...simple....

Polish the chambers like a mirror or have them coated. This is to keep the heat (energy) in the chamber pushing down on the piston instead of going to the cooling system.
This will also keep from having a hot spot in the chamber. (preignition)

I am runnig an Edelbrock Performer and a stock type Rochester QuadraJet.

Stock type HEI.

I fully expect to get double digit milage towing a 40 foot race car trailer.

Mileage is a relative thing, I expect 10 or more mpg when I'm done, somebody
else would say I'm crazy with only 10 mpg.

It would be a 30% to 40% improvement.

Currently getting 6 to 7 mpg towing, so that would be great to me.

Just my .02

CCDually