The Stovebolt Site Forums The Shop Area Engine Shop towing with my 66

well I got my class 5 hitch and electric brake controller hooked up to my 32 foot trailer filled the tires with air was not able to get all lighting working but had my wife follow me the truck pulled the trailer pretty good but it did work the motor hard 292 going up hills had to get the speed up am probably going to have to tune the engine it had a small miss in the city had one big hill that i had to stop on and could not get above second gear until over the top one question I have I have a spare HEI ignition if I install this will I get more power I want to keep the truck original but I could have used a little more HP also saw the post on 4 barrel carbs maybe have to do this down the road for towing with the placement of the wheels on the trailer seemed to make bends well although looking in the mirrors seemed like the dump bed was going to hit the front of the trailer but it never did when making turns I am using it in a week to go on a 100 mile trip the only thing is I might have some people mad when I hit the mountain hills but I'll be mostly on the highway.

Thanks Dave

The HEI probably won't help much with the power, but it will cut down on spark plug changes. The HEI coil has a minimum open-circuit voltage of 25,000 volts, and a good one will exceed 50,000. This makes sure the spark plugs fire every time, and they don't foul out as much as with a conventional ignition system. Also, switch to an AC "commercial" spark plug. They have a "C" prefix before the plug number, like a C45TS, for instance, instead of a 45TS. We use the commercial plugs in the race engines, and get more than twice the lifespan of regular plugs. Don't waste your money on platinum plugs, or other gimmicks! When you switch to the HEI distributor, have a good driveability specialist recurve the centrifugal advance to the same specifications as a medium-duty truck. It's probably set up for a passenger car now. If you've got the distributor number, I can probably tell you what it's supposed to fit, and what the current advance curve is. If you plan to do much towing with this rig, you probably need to install flat-top pistons and an RV-type camshaft for more midrange torque.

Edit: I just looked up the distributor specifications. The correct part # is 1110679 or 1110680, for a 1977 250 or 292 heavy-duty engine. Centrifugal advance should be 0 degrees at 550 distributor RPM (1,100 engine RPM), and max advance of 12 distributor degrees at 2,050 distributor RPM (4,100 engine). Distributor degrees are doubled, meaning your centrifugal advance will be 24 degrees over the initial timing, without vacuum advance. This is important! One degree over-advanced robs as much power as 5 degrees too late. I've proved this numerous times on the dyno. Vacuum advance on your distributor should start moving at 10" of vacuum, and it should get a maximum advance of 5 distributor degrees at 13 inches of vacuum. Vacuum advance goes away almost instantly when the engine comes under a load, so it's only for part-throttle cruise fuel economy. Good luck!
Jerry

Wow lots of info probably wont get into pistons and cams though as I won't be towing often great info on HEI and plugs I didn't know they made a comercial plug I probably won't change the ignition this week as I won't gain any power but still might do in the near future how about the 4 barrel carb the guys that tryed this did it help in power anyway I still have a lot to do to the trailer but am going to look for the comercial plugs

Thanks for the info
Dave

If you can find a spare intake manifold, I'd suggest adapting a Holley #7448 350 CFM 2-barrel to the engine. Just using an adapter plate probably won't help, because you need to open up the throttle base area for more airflow. We use the same carb on the 350 V-8 race engines, and make over 300 HP at 6,200 RPM. The 292 engine should wind up to 5,000 RPM or more on this carb easily, and you can gear the rig accordingly. Also, the Holley is VERY adjustable in the main jet and power valve department. I keep at least 6 sizes of jets and 4 different power valves in the race tool box all the time, to compensate for temperature, atmospheric pressure, and humidity changes on race day. JEGS sells those carburetors for about $250.00, brand new.
Jerry

Again thanks lots of great info how about high octane gas always thought for old valves and such was bad but for 200 mile total trip would it help or hurt the engine might as well absorb all the info you even got me thinking about the pistons and cams although I wanted to see how many miles I could pull out of the stock engine as of now 66,000 on engine when I had my 79 chevy with 350 engine had well over 200,000 on it and the buyer drove it away

Thanks again
Dave

Try some mid-grade gas, 89 octane, I think it is. You won't have enough compression to benefit from premium, and it will actually make less power, and cause the exhaust to run hot because it burns too slowly. If your timing is a little on the early side, the mid-grade will let the engine lug a little without detonating.
Jerry