Total agreement on the numbers being out of whack.  What were the lobe lifts when those numbers were being recorded?  As a general rule, lobe lifts are checked at 0.006" for hydraulic camshafts and 0.020" for solid lifter camshafts.  I’m assuming that the exhaust is opening at 118° BBDC and closing at 62° ATDC?  If that’s correct, then the duration for the exhaust is 360° while the duration for the intake is 344°.  360° is a full revolution of the crankshaft.  If that 118 number you posted is 118° ATDC, then the exhaust is actually opening at 62° BBDC which would make more sense.  Without clarification on the numbers, the problem lies with both the intake and exhaust lobes.  Did you check the lobes on a cylinder on the opposite bank as there’s also the potential for the camshaft to be ground on the incorrect lifter bank angle which just compounds the problem.

Lorena, Texas (South of Waco)

If you could post a copy of the cam card sent back from the grinder that would be helpful..

It's been too long since the grind, sorry, no card. As far as the exhaust numbers go, we have them at 116/65, just a little off from stock. We didn't go 100% on checking every cylinder. Once Jeff found the large discrepancy he knew where the problem was and pulled the cam. Stock grind going in. I was hoping for a few more ponies but I guess I'll have to settle for my amateur porting job. The last heads I did for my 56 Mark II came out great.  These are Merc heads and had a little more casting to get rid of. Maybe it was just the supplier that was different, who knows. Uh-oh, you say, what did that knucklehead do to the heads?  Not to worry, just made the gaskets and the holes match up on the intakes and exhausts.  I know that sanding down the runners smooth only works best for high RPM builds.

We're up and running. Cam swap did the trick. All cylinders at 145. Now for the fun part(?) Fabricating the webbers with linkage, fuel delivery, and transmission linkage.  Still looking for generic linkage and fuel systems on the internet.

You will likely have to do your own linkage design with bell cranks heim joints and turn buckles.. Kinsler fuel injection has all kind of weird hardware to make their injector linkages work.  You might look at their catalog.. You might also get some help from Alkydigger .com  he does custom linkage setups for Hilborns which pose similar problems as your webers. Glad you got that 368 running   Now let's make some horsepower!

Vacuum is going to be an issue. With my custom made adaptors which fit between the runners and the heads, there's no good place to get vacuum. I know external is an option but checking vacuum for tuning has got to be in the equation somewhere.

Do Webbers not have vacuum ports for that purpose?


Lawrenceville, GA

To get an accurate vacuum reading you need to have a common plenum.  With IR type induction you can't get a good reading because of the pulsing of the intake tract... The same problem comes up with IR injectors converted from mechanical to EFI.. It is solved by tapping an 1/8 pipe fitting (or smaller into each injector then running the lines to a small common plenum, then taking the vacuum readings off of that.  I will see if I can find a picture for you

https://www.alkydigger.net/proddetail.php?prod=AD-Vacuum

For balancing Weber carbs, I use a Unisync tool.  Works also for individual throat fuel injection or those manifolds where the carb venturies are being aimed at specific cylinders such as when using the Man-A-Fre manifolds.
 

Lorena, Texas (South of Waco)