Now, you said you have installed a 160-degree thermostat to the mix. You also mentioned that the hesitation seems to be less the warmer the engine gets. This sounds like the engine could be on the lean side, and the cooler the engine runs the more pronounced. MagnaCharger is constantly refining its calibrations with new tuning variations. Your best bet is to contact the company and make sure you have the latest calibration for your vehicle. Also, don't forget to mention you're running the 160 stat. The calibration is based on the engine operating on the factory 195 thermostat; this could be most of your issue. MagnaCharger can bring your Silverado right into line.
Q: I have a '69 Chevelle with a newly built 383 stroker, a 280 Comp Cam camshaft, an Edelbrock Performer RPM intake, an Edelbrock 800-cfm carburetor, Top Line aluminum heads, ACCEL 416 S short header plugs with a 0.045 gap, a Mallory distributor, and timing at total advance of 3,000 rpm at 36 degrees.
The engine runs great, but my problem is that when I turn it off, half the time it diesels. Any suggestions?
A: Dieseling usually comes from combustion chamber heat and a carburetor in which the throttle blades pass too much fuel and air at idle. With your Comp Cams 280 camshaft, you're probably running an idle speed of 800-900 rpm. With the throttle open this far, it's a prime candidate to run on, and on, and on!
First, make sure your Mallory distributor's mechanical advance is closing back to your base initial timing setting at idle. Sometimes after revving the engine up and having a higher engine idle speed, the springs in the mechanical advance can't close down the advance. Once this is corrected, pick up an Idle Compensator Kit from Edelbrock (PN 8059), a 12-volt solenoid, and a mounting bracket that attaches to the carburetor. This kit is usually used for holding up the idle speed when the A/C is engaged. You'll want to send 12 volts to this solenoid whenever the ignition is on, and use it to set your base idle speed. Back off the carburetor's idle speed screw until it just barely keeps the blades open. This will close the carburetor down to basically no air and fuel when you shut off the ignition, and the engine will stop. This is the best way to control pesky dieseling issues. Back in the early '70s, all GM vehicles used some type of idle dashpot (this is what they called them back then) to set the idle speed. This prevented engine dieseling.
Ain't Going to Be Smooth
Q: Where can I find out how to swap a big-block Chevy into my '95 Chevy Camaro? I already have the engine and just need some info on what should be done to make the install go smoothly.
Alta Loma, CA
A: That would be a very nice swap. However, with the design of the fourth-gen Camaro, GM pretty much shot us all in the foot for a big-block engine swap. As you know, half the engine sits underneath the windshield. Also, the engine can only be removed or installed from below. With the height of the big-block engine and any type of performance inlet manifold, the carb is in the base of the windshield. We've seen a couple swaps into drag race cars. They had handmade tubular front subframes, engine mounts, and totally custom headers, and the cowl was cut back to the windshield to clear the four-barrel throttle body. You couldn't even put a Holley carb on this thing because the float bowls wouldn't clear the glass.
If you want to pick up a very clean third-gen Camaro, it will accept your big-block easily. Sorry to not have an easy answer. Again, it would be a cool car, and it can be done if you're willing to cut the car up and do a complete custom installation.
Technical questions for Kevin McClelland can be sent to him at firstname.lastname@example.org.