440 Rebuild time. Your thoughts welcomed.

[66 Charger]

When I purchased my 66 Charger it came with a stock running 440 block stamped (2536430.3 1966-72) in it. Also I was given another 440 that the guy said it was a "race engine" (3698830.440.9 1973-75) I knew nothing about it and never heard it run. He did have a receipt from a speed shop in Long Island,NY.
On this "Race Engine" it has Edelbrock Performer RPM Aluminum heads (84cc). It also has a Comp Cam Magnum 306S Mechanical Flat Tappet Camshaft
Lift .555"/.555"
Duration 306°/306°w/ Solid lifters RPM range 3500-6500
Crane Cams® 64791-1 - Gold Race Pro Series Shaft Mount Rocker Arms
Speed Pro .030 Over, 12.1 domed pistons (w/ 84cc heads on the 440 I'm guessing it would have 10:50:1 compression).
Anyway, I used the running stock 440 during the restoration to move the car around. I cleaned up the "race engine" and replaced the rod and crank bearings, new HP oil pump. I put it in the car behind my 4 speed and it has a loud knock which was comping from what we can hear from under the intake. We did adjust the rockers before installation and after the first start up we heard the knock so we went over the rockers two more times. After that we thought it may be a bearing so we replaced the crank and rod bearings after the rocker adjustments.
There is a lot of oil pressure and we put cut out valve covers on and can see plenty of oil circulating.
At high RMP's the knock is still there.
So I was thinking on either brining the "race engine" to my machine shop and have them go thru it to see what they fine and or do a rebuild on it.
or
Take the stock (2536430.3 66-72) and bore that out rebuild and use the Edelbrock heads on it.
BTW engine only has a single 4 barrel carb on it at this time.
Suggestions??? Thanks in advance..

 

[Mike67]

Did you check piston to valve clearence? You can take a long screw driver, broom handle and with the engine running put it on each header tube and your ear on the other, you should be able to hear which cylinder is having the issue...
Good luck!

 

[Carcinogen]

I would re-do the stock engine with forged flat tops and mild cam for reliability to get the car moving, then when money and time allow get the race parts engine together.

Might find you are happier not having to find race gas to support the race engine's domed pistons.

 

[dvw]

Before uou damage somerhing. Do it right , pull the motor. Tear it down and see what is wroung. Measure the actual compression ratio, degree the cam. That cam will work with the proper compression and converter. Should be an easy 11 second piece. If you don't have the experience find someone who does.
Doug

 

[68 HEMI GTS]

Piston slap? Speed pro's are usually set pretty loose. How did the old bearings look?

 

[moper]

Are you measuring the crank journals before you slap bearings on them? Not with plastigage... I mean actually measure them with a micrometer. If the journals are tapered, or sized differently, you could have a problem. Also check for interference between the pushrods and heads or maybe an intake bolt.