[Cliff R]

Three things need to happen here.

First, you need to verify the intake open point to make sure the cam isn't retarded. A little to late now (without a LOT of work) to set it all up with a degree wheel and piston stop to find TDC. Just remove the drivers side valve cover and slowly rotate the engine until the #1 intake valve starts to open. If you have the means put a dial indicator on it and stop at .050" tappet lift. Glance down and see where the timing mark is on the harmonic balancer. Reference the cam card and see if it's close to the listed specs. Of course this assumes that the balancer was checked during the build and hasn't slipped some.

Next, rebuild the carb with high performance parts and tune it for the added power, I can help with that. A stock carb is WAY too lean with the huge DB rods in it to make any power with the cam upgrade.

Remove the distibutor, drive out the roll pin, remove the gear, pull the shaft out of it and clean, polish and lubricate all the parts in the mechanical advance mechanism. I would also weld in a positive stop for the advance in case you install lighter springs to get the timing curve in a little sooner.

A larger cam without a corresponding increase in static compression is going to loose some vacuum at idle, power right off idle, and shift power up in the RPM range. Typically when this happens the engine will want more idle fuel, and more timing, and all in a tad earlier than it did with the stock cam.

I did see any mention of what head gasket was used but hopefully it was a Felpro at .039" thick and not something in the .050-.060" range which would just take more power out of it.

I'd also add here that I've used that cam in quite a few low compression 400 builds and it acts like a pretty "big" cam in them. It will make great power as well. The first engine in my Ventura was a low compression 400 with 6X-8 heads and it ran high 13's over 100 mph with that cam against a stock converter and 2.73 gears. It would rip the tires right off the rims on a full throttle blast from a standing start and took some work to get it to hook at the track on street tires.

If your nearly identical engine is a big "turd" you are missing a few things and need to figure them out. I doubt if it's how deep the pushrods are in the lifters. I ran the stock bottleneck studs on my heads but simply added adjustable 3/8" locknuts to them......hope this helps some......