My current project is making my NOM engine at least look right, in parallel with an ongoing search for a correctly date-coded block to rebuild a L76. What I have is a '66 "174" block with '68 double hump heads and most everything topside incorrect. In addition to replacing the incorrect carb and intake, I am replacing all the incorrect "fiddly bits", such as hoses, lines, etc.

This weekend, while stripping the topside, I went for it and pulled the heads to see what was in there. It's got what appear to be Speed Pro forged pistons at .030 over, with a good cross-hatch on the bores, and no ring ridge; however, these are not the correct pop-ups for a L76. The heads have what appear to be 1.94 intake valves, vice 2.02s, and are in good shape. The combustion chambers have a light carbon build up, but not bad. The cam is some unknown hydraulic cam, and the lifters and lobes look like new, but this is clearly not a L76 cam.

The engine can be easily turned over by hand with the heads removed, and I have had no indications of rod or bearing noises of any kind. Also, oil analysis looks good. My plan is to reassemble the engine with the original short block and heads and with the correct Winters aluminum L76 manifold and Holley 4510 (2818-1) carb for now, and drive it for a few more years.

Here's my question: Will this be too much carb for this setup? Since I'm this far in should I pull the cam to see what it is (or can I use a dial indicator to get cam specs from the lifters or push rods)? I'm really not interested in doing a full overhaul on this engine, but would you pull the pan and mike the bearings?

I recognize that this is all over the map - but that opens up a wide range of responses.

Thanks for your thoughts in advance.

 

580 or 600cfm, vacuum secondaries, sound like you have replacement 327/210 hp pistons, but those heads will wake it up tremendously.
Lane

 

ER - Before you started taking the engine apart, did you happen to do any testing like compression or leakdown? What's the casting numbers off the cylinder heads. It sounds like the engine is in good shape but just not built to the original L76 specs. You're not too far from pulling the engine at this point if you were thinking about going back to a solid lifter cam and maybe freshening things up a bit. As for the pistons, back in the late 70's through around early 90's, the prevailing thought at some machine shops was to drop the compression to avoid detonation so that might explain the flattops. Regarding that carb, as faslane mentioned it's probably rated at 585/600 cfm and that size carb is just fine for street duty.
Mike T - Prescott AZ

 

You could drop a solid lifter on a couple cam lobes and use a timing tape on the balancer to figure out lift and lobe separation. The results should be fairly accurate.

Verne

 

Easy Rhino,
are you still looking for a date code correct 327/300 hp for your car? I have 66 Coupe with the number matching engine and transmission that I am looking to sell. It doesn't have the correct water pump or the factory intake or exhaust manifolds. I am looking to go with an LS engine so I am selling my engine. It only has 400 miles on it since being rebuilt and is still in my car and running. I bought it from a collector who had it completely frame off restored and the engine and transmission (powerglide) were both rebuilt as well as the heads were gone through. I have the receipts for everything. It was done several years ago and then put into a show room and never drive, there are no oil leaks.
Nick

 

As I read it, you are asking only if the carburetor is of the correct size? Sounds like the engine is almost new. I agree with checking the cam lift off of a solid lifter or the rim of a hydraulic lifter.
I have found that a Holley 585 or 600 cfm vacuum secondaries to be perfect with the small blocks unless you are running a high lift cam and manual transmission. I have 4 or 5 left over from the 60s and 70s. I went to 650 and 780 cfm double pumpers on the drag strip with a full tilt 302 / Z28 motor, 13.4 to 1 pistons and high lift cam, but they are not good on the street with a 10:1 motor that you need for todays gas.

There are plenty of 66 327 / 300 hp engines out there if that is what you are looking for. I have a spare one with correct block and heads for a 66.
Heads 3782461 (double hump) A266 (Jan 26, 1966) 62 cc, 1.94 intake, 1.50 exhaust
Block F020IHCH Flint, Feb 01, power glide, Holley carb - used in Corvette and HP cars
3858174 date code A266 (Jan 26, 1966) if you are looking for a numbers correct, but not an original Vet motor I might be willing to trade or sell. I need to mic the cylinder walls to see if it is still rebuildable as standard, but very little ring ridge.