Eric...I have a 268H in my 355 and am getting around 13-15mpg with 3.31's if that helps any....
Jul 15th, 00, 06:26 PM
Running an Edelbrock Performer in my 70. 355, 9.7;1 comp, 1.6 full rollers, five speed, 2;73 rear. Can get 24 mpg mostly highway driving. Good power up to 5000 rpm, not much above that. Hard to beat for my setup.
Jul 17th, 00, 05:03 AM
My 67 has a 355 with edelbrock air gap intake, AFR 190 heads, 9.5:1 compression, Holley 650 carb, afterburner headers, 2 1/2" exhaust, 3.73 gear, 700R4, and 2500 rpm stall with lock-up. I have a comp XE270HR hyd roller cam (218@.050) with 1.6 roller tip rockers. I get 17-18 mpg and 13.08 at 108 mph in the quarter. I would use the split pattern XE cam over the single pattern cam for a street car. A friend of mine has the XE 262 cam in his 355 and he loves it.
Jul 18th, 00, 09:05 AM
My combo is very similar to Squarles' except I have a 3.08 rear and Performer RPM heads. I get 18-20 MPG. The car ran stronger when I had 3.73s but I drive 100 miles R/T to work.
Jul 18th, 00, 06:20 PM
I dont see how you are getting such good gas milage. I have a holly 650 double pumper, mild cam, 3.35 gears, and stock GM heads and I get less then 10 miles to the gallon. What is the secreat to better gas milage?
Jul 18th, 00, 08:16 PM
Lots of little things add up to make for good gas mileage. The only secret I know of is to put an oxygen sensor with a readout meter on the car. I got the Edelbrock outfit for mine. Spend about 6 months, took the carb apart maybe 10 times before I got it really dialed in. Better mileage and more power too.
Jul 19th, 00, 07:01 AM
The secret is overdrive. All other things contribute but the biggest reason is overdrive.
Jul 19th, 00, 07:21 AM
Overdrive is definatly the way to go. Proper fuel mixture and a good ignition system is important also. I did not list it above but I have a MSD 6AL and a stock point type distributor with a unilite conversion kit on my car also.
Mark W. Winning
Jul 25th, 00, 09:53 AM
I have always found that gas mileage and Holley are not always the best match. Adding a double pumper to the mix really hurts. Don't get me wrong about Holley, I love them for power, but I don't expect much else from them.
Jul 26th, 00, 04:39 AM
Hey I have a 396 bored 30. I am running a 9.6 compression ratio, stock sized valves,stock exhaust manifolds with 2 & 1/2 pipes with flat turbo mufflers, cast iron holley intake, a 600 cfm elderbrock carb, a 268 XE comp. cam, a m-20 4speed & 3:08 gears. I got 17.5 mpg on the last tank of gas on this combo, & have power from idle to 6000 rpms. I love the way this cam sounds & runs
Jul 26th, 00, 02:42 PM
I am still learning about the small block engin. I am just amased at the gas milage you are getting. If I were to put a Ox sensor in my system, what would I look for. Does the fuel miture get leaner as the engin excellerates? I have no clue where to start.
Jul 27th, 00, 02:30 PM
A very good cam for mileage and torque is chevy's old -929 hydraulic out of a 195hp 283, 250/300hp 327, 295hp 350 and I think the 265hp 400. It's got .390"/.410" lift and 195/202 duration (or there abouts)at .050".
My stock 67ss camaro's L48- 295hp 350 with an M-20 four speed and posi 3.31 gears used to get 16 to 17 mpg if I didn't drive he-- out of it. pdq67
Jul 27th, 00, 02:35 PM
Thanks to David Pozzi, here's a site that will show you how to make your own $30 O2 sensor. It works. I finished mine last week and will be doing more tuning after the new cam is in.
Click here to see see my car and hear 5-speeds. http://www.geocities.com/casanoc