| There were a number of goals I had in mind when undertaking this project. Below are some of the problems and what I planned to do about them. |
| Problem | Proposed solution |
| Detonation: with the gas available these days, this was quite a problem. Most solutions would reduce performance. | Reduce compression, but increase flow to counter loss of compression (hopefully). The heads I had, now with bent valves, gave me 10.5:1 compression and had small valves. So bigger valves, and increased lift was in order. New heads w/ some porting. Higher rocker ratio. |
| Induction: carb got hot, motor ran out of breath just over 5000 RPM. With 4:11's, I wanted the motor to be happier at higher revs. | Scrap stock cast iron intake, block exhaust crossover, go with aluminum intake of type that would promote breathing at higher RPM's, insulate carb from engine heat. Some form of cool air access. |
| Street manners: idle quality, low speed throttle response, etc. | "Variable duration" lifters, slightly lower stall speed. |
| Cooling: | Here I hoped that the rebuild would cool things off, as well as a real multiblade fan with clutch, the aluminum intake, the hole in the hood, and a tranny cooler (since the stall converter would obviously heat things up driving around town) |
| Transmission: whining, leaking, I needed a more reliable set up. | New tranny, heavy duty options. Cooler. New, more streetable converter. |
| Traction and handling: the bias plies rode rough, and they weren't very sticky. | Radials were in order. Fat as possible in back, as the 4:11's are tire burners. The aluminum rims would have to go...they weren't wide enough to hold BIG tires, and they were only 14" diameter. |
Specs. After Build:
| Block | 1964 Pontiac 389 cid bored .030 (394 cid) 11H code
Cleaned, honed, ridge reamed, painted, etc. all new Clevite 77 bearings TRW high pressure oil pump. All inner surfaces painted with high temperature coating to seal pores and prevent block impurities from contaminating oil and to promote drainback. THIS WORKS!! Oil changes have never seen such clean oil and it FLIES out the drain plug. It looks cool too. |
| Crankshaft | Pontiac "Armasteel" turned .010 |
| Pistons and rods | Stock rods, new bolts.
TRW flat top forged aluminum pistons. TRW rings....last set for .030 389 that they could find in the country....That was 12 years ago! |
| Heads | '73 4X heads 98cc, milled .050 to 88cc (approx. 8.5:1 estimated)
2.11 intake, 1.66 exhaust Built by RHS (used to be same company as Comp Cams) Some porting, bowl and runners. Gasket matched. Chrome moly retainers/locks Heavy duty double springs Screw in studs Pushrod guide plates |
| Rockers | Comp Cams "Magnum" roller tipped rockers 1.52 ratio |
| Pushrods | hardened for use with guide plates |
| Lifters | Crane "Hi Intensity" variable duration lifters, supposedly "like Rhodes but without the noise"....not true....still noisy. |
| Timing | Cloyes "True Roller" double row |
| Camshaft | 278/290 advertised, 222/234 @ .050
.467/.494 lift (.473/.500 with my 1.52 rockers) 114 lobe separation, 56 overlap |
| Intake | Offenhauser 360 degree, single plane/divided plenum, aluminum.
Port matched to heads and gasket. Topped with 4 hole 1" phenolic spacer Exhaust crossover blocked. |
| Carb | Holley 800cfm double pump mechanical secondaries
Topped with K&N velocity stack/air cleaner combo |
| Fuel delivery | Holley high volume mechanical fuel pump
1/2" aluminum fuel line from tank forward |
| Exhaust | 4 tube headers, 2 1/4" pipes w/ "Sonic Turbo" mufflers |
| Ignition | Prestolite Electronic Ignition
Accel "Super Coil" stock distributor (minus points) and adjustable vacuum advance. |
| Cooling | 4 core radiator of unknown origin, 5 blade steel fan w/clutch
(contemplating electric) |
| Transmission | later model Cadillac Turbo 400
Built by Grans Trans of New Haven 34 element sprag assembly and hardened input shaft When asked how hard I wanted it to shift I replied "I want it to rip the cross member out!"......a few weeks later, it did. Redesigned cross member mounts afterward. Mounted largest B&M transmission cooler they made in front of radiator, using extra deep pan. |
| Torque Converter | B&M "Holeshot" claimed 2200-2400stall, I see about 2800 on hard launch. |
| Rear | 10 bolt 4:11 from GTO |
| Wheels & Tires | Front:15x7 Chevy rally 245/60R15 BF Goodrich Radial T/A
Rear: 15x8 Chevy rally 295/50R15 BF Goodrich Radial T/A |
| Suspension | Front: 3" lift heavy duty springs / KYB Gas-A-Just shocks
Rear: 3" lift heavy duty springs with spacers for extra inch or so Heavy duty coil over shocks w/extensions Ladder Bars |
| Gauges | Tach, temp, alternator, fuel pressure, vacuum, oil pressure, transmission temperature. |
Conclusions:
| Overall, good results. The average temperature
is a lot better, it's road manners are fine (good idle, quiet converter,
good low speed driveablity and throttle response). It handles very
well and is a joy to drive on curves, hills, stop and go, and even in the
woods! The tires make it smoother and traction is much better. The
highway is still a drag.....though everything stays tight and runs smooth,
the engine is revving higher than is comfortable for long periods, and
this thins out the oil, leaving me with very little pressure at the end
of an exit ramp. This is to be expected with the 4:11's however.
The biggest changes were from the change in compression and the new induction set-up. There is no replacement for compression!!!! Granted, I had little choice with fuel availability and the extent to which it was detonating, but there was a noticeable loss of torque throughout the range, but especially at the bottom end. A little less of that "seat of the pants" kick at take off. It NEVER pings anymore, no matter how far I advance the timing! I can easily put it right where it needs to be now without worry. On the other hand, I gained an easy 1000 RPM from the induction/head/valve train combination! Under full stoplight racing conditions, I am now shifting near 6000 RPM. If I don't watch very carefully, it will slam past that. Though I've seen 6200 or more, I set (mentally) my limit at 6000. I really should put rev limiting on because everything happens so fast. No sooner do I get traction and it's time to shift....and again by the time I get my balance back it's time to shift again and it's almost time to get off the gas. I never see fuel interruption any more, and it winds up very consistently. Mid range to upper mid range is incredible. If I had more compression (and a little less gear) I'd be tempted to bump up the duration even more since it seems to have unlimited breathing at this point. Even with the 50 series tires it still breaks loose on launch, but not much if I do it right. The transmission rocks. Huge chirpy shifts even at low speeds. Gripes: Holley carbs run well but don't last long.
Where is it now? In my parent's garage, having sat for 5 years after I moved away to my own home. Now separated and moved back, I will be putting it back on the road. Mechanically it needs only a starter and carb, but cosmetically I have some body damage to fix that happened just before I stopped driving it. |