Senior Tech Team
Join Date: Dec 2004
Location: Belle Plaine, MN
I used the AFR CNC-finished heads as-delivered, but I did change the valve springs to the recomended Comp units. They were not cheap, but I didn't have to do anything to them (except the coating treatment and the valve spring change). I used the RPM Air Gap intake out of the box (untouched- not even port matched).
It's a solid roller XR 286 (PN 12-772-8). I planned to run a solid roller from day 1. I used Comp's composite gear on the MSD dist. and it runs a normal 6AL box. I wanted the Lunati Pro kit because this engine may see spray or a blower in the future (hence the low compression diet of 87 octane now).
If you ahven't heard of Calico Coatings, you're missing out on some almost-free horsepower. Yes - Coatings cost money, but the parts don't have to be modified to be coated. I chose the thermal barrier coating (a kind of porcelain) to insulate the chamber (gotta keep heat in aluminum heads), and to eliminate any sharp edges from the chamber (no hot spots since I'll be fighting detonation on 87). I also coated the ports (the intake to keep the incoming charge cool; the exhaust to keep the outgoing charge hot), and the valves to help both.
A 750 cfm Holley could work, but I got the Demon so I could play with the venturi sizing. It's crispy and responsive at 825 cfm (green sleeves).
The car ('67 Malibu Wagon) is getting a Rockland T-56 (good to 600 ft-lbs), so stall will not be an issue.
I feel 10-10.5:1 would be fine with 91 or higher, but I really wanted to see how much I could get on 87. These numbers were generated at Westech with 1.75-inch dyno headers and 3-inch in/out Magnaflows. No air filter was used, but I do run one on the street.
I temporarily installed the engine in the car with the stock (original '67) Powerglide/converter. It does run, drive, etc. but is less than optimal. Knowing the 6-speed was in the cards made it okay. That greasy 'Glide does not appreciate the newfound torque...
I'll be building on this car on the pages of Street Thunder magazine. If any of you folks got a mailed invitation to join the National Street Car Association car club, Street Thunder is the club magazine. I'm the Editor.
The car will be getting a 9-inch to complement the rest of the drivetrain and already has Hotchkis susp. and big brakes. It will be tested everywhere (dragstrip, road course, skid pad, etc.) and results will be published on the performance of the 87-octane 383 in this car. I intend to fine-tune the combo to it's full potential.