I have a friend with a late model 455 w/ 4a heads on it.
Did a little searching and cant find much on this set up.
Any real benefits to going this route?

 

None whatsoever. Small ports, small valves, and crappy "lightweighted" castings. Port mismatch causes a flow disruption on the intake side. 4A heads are crappy on their original 403 and only get worse on a BBO. I use a set as ballast for my swap meet canopy.

 

That is what I figured.
Will talk him into some better heads.

Thank You.

 

I also used a pair, along with cracked factory Dodge Magnum heads to counter weight my engine hoist, when I extended the boom. The 4A exhaust ports are horrible with tiny 1.5" valves. My set CCd at 86, so no help at all in the compression department either. How does the motor perform?

 

And since the 4A heads are late-70s "lightweight" castings, they even suck at being ballast.

 

Non running engine stand holder.
First time I saw it.
Somebodys "its got to better" idea.