CabSav

At the moment I’m just dreaming about maybe doing a rebuild on my 66 427, so I was wondering whether a few of you might give me your thoughts on this please.

I have a 961 block with the oil cooler holes above the filter.
702 heads
an 848 intake
a stock dist. with Pertronics
a Holley 3247
STD 827 & 828 exhausts to side pipes
I have no idea what cam is in it, but the previous owner did mention 30-30
I have no idea if I have hydraulic or solid lifters

Classic Air
No power anything
Original cooling system
I’d like to keep it as stock looking as possible without being stupid.

And I’d be aiming for somewhere near the original 425hp Gross, for street use only in a mostly very warm climate, so with this in mind, would I:
a) Massage the 702 heads, bigger valves, cam etc?
b) Cough up the 3-4K for some 858 heads & 069 manifold, because we know they fit.
c) Replace the heads with aluminium after market units

Being based on the other side of the planet means I shouldn’t take hit or miss shots at manifold clearance or valve cover clearance etc, returning stuff from here is a real PIA.

Thanks everyone,
Pete

66BlkBB

I thought that the 30 -30 cam was a small block cam but I could be mistaken. You should be able to tell whether it is a hydraulic or solid lifter cam. If you hear the tappets clicking and the engine revs to over 6000 rpm I would believe that it is a solid lifter unit. If the engine runs smooth with hardly any tappet noise, then I would have to say it is probably a hydraulic lifter unit.

JohnZ

The 702 oval-port heads and 848 iron intake (if original to the car) say it's a 390hp, but the holes above the oil filter say it's a 4-bolt; what's stamped on the pad forward of the pass. side cylinder head?

If you're looking for 425hp, you've got a lot of spending ahead of you. Remember that any cam you use must have a groove machined in the rear journal or you won't have any oil to the lifters.

midyearvette

if you dont care about originality, then do not go with the 858 heads, they are very expensive and new after markets are much better....you will have to make the decision of oval port vs. square, then again the after market stuff is a better choice if originality is not an isue..also the heads and compression ratio will tell you which cam to pick, newer style after market heads, especially in the oval ports are very good to 6000 rpm with plenty of power and torque, the square ports are better from 4000-7500 ...good luck.....

CabSav

Thanks 66BlkBB,
You are probably correct on the 30-30, I wasn't really paying that much attention at the time.
It signs off at 5000 rpm & has no tappet noise to speak of, so it must be a hydraulic cam.

Thanks,
Pete

CabSav

John, the engine number pad has been ground flat & I seriously doubt that it's the original engine.
It has
HI PERF
PASS
K 23
cast into the block near the oil pressure pickup.

I'm happy to go with after-market heads. JEGS sells GM alloy heads for about a $1K, are they ok?
Then my biggest concern would be a to find manifold to under the 3247 but still have hood clearance.

Thanks,
Pete

midyearvette

just about any after market head will be better than stock especially if they have bronze wall valve guides, your head choice will be determined by what you want out of the engine....this will also go with your intake choice....the edelbrock performer rpm intakes will be a challenge for hood clearance....the stock chevy intake for the 425 engine is the tallest you can run and still keep your choke tower and have hood clearance but you must run a drop base aircleaner....good luck.....

Avispa

The 3247 carb is from a 425HP motor. You can get a lot out of putting in 1.88 inch exhaust valves, a three angle valve job, Comp Cams 1.72 ratio Magnum rockers (will fit under the stock covers), and a decent solid lifter cam (even for oval port heads). I have Crane's mildest solid lifter cam and it whizzes right through 6200 RPM wothout a hiccup. The setup with rectangular port heads and 10.2 compression made 454 hp on the dyno. You should be able to do that easily even with oval port heds.

The factory iron manifold needs help. An Edelbrock Performer RPM (NOT the Air Gap model) should fit under your hood with a stock air cleaner.

CabSav

Thanks all for your comments, thats the sorts of stuff I need.
Pete