really Bob i get concerned sometimes people misconstrue things i say. i don't consider myself to be some crack engine builder but i would think the mild 451 has to be making close to an honest 600 to push 1800# 160+. there's nothing really trick about it either that's with a 4150, flat tappet and 11.5:1 CR. of course you can make more easier with more inches and better parts plus have the ability to increase output in the future but i guess i just try to be conservative.

the rpm head has no problem going to 600 but i would change the springs/retainers and do some clean up on it. also as mentioned using a lo deck helps with the A body fitment. i just assumed most people are going to use fenderwell headers on these. though they're not a particularly friendly header the options are very limited header wise. i don't use cheap parts because in my opinion and experience of others it's false economy. i do have a 3.91 chinese crank i might be putting together in the near future but that's the only imported part i have around. now i'm not saying everyone needs a callies or the like but chinese rockers, heads, rods, dampers etc will not be found in my collection. i've seen a pair of those chinese heads right out of the box with a retainer/lock assembly that probably wouldn't have survived break in without falling in the cylinder.

connecting rod selection has become dicey because most are using imported forgings. the manley sportsmasters were a nice rod but manley decided they could make more money using foreign forgings. anything above the import stuff is usually north of $1000. i do believe there are some vendors doing better finishing and quality control of the import stuff.

imho i absolutely would not use that manifold or rockers and personally though a fair number of people have been using the chinese heads i won't and wouldn't