Hello everyone,
I've been slowly building a 70 455 for my 69 442. Awhile back I asked for advice on what needed to be done to get to 450 HP 500 TQ. with stock intake, heads, Carb, exhaust manifolds. Thanks again for all the help and input. Here is were Im at so far the block has been line honed, block has been square decked @ 10.620. They also have the ability to true up the angles on the cylinders which I had them do. its been bored .030 over. I have removed the AIR bump from the exhaust port on the heads. I've decided not to fill the crossover because im keeping the devorced chock. 1st QUESTION : If I'm not filling the cross over is there any benefit in welding the center exhaust divider and can I MAG weld the divider with silica bronze? (melting point 1850 degrees just a few 100 degrees under steel). My 2nd QUESTION: Can anybody help me figure out what my CR will be. the crank has been ground .010, the CC's on the factory E heads are 80 the connecting rods are stock but I may buy Eagle H beams as recomended. The pistons they purchased are Race Tech. (AutoTec small block custom inverted dome) -15cc milled dish, 4.155 bore Dia.,1.750 compression distance. Thats all the info I have on them. They are recommending I keep the CR down at 9.5 due to the 90 octane. One final question if I could. How much HP?TQ can I pick up going with roller cam lifters and rockers is it worth the additional cost? Thanks again for your help.

 

About 9.75:1 as that piston will be about .010 in the hole with that deck height. That piston is my design btw. The only thing they had available before was a 6cc flat top. I’ve done dozens of sets with them, good piston. Hopefully you got them with the metric ring pack. Get the Eagle rods too.
Buy a wideband O2 and tune it right, you should be able to run 90 in if it’s tuned correctly.
Fill one side of the crossovers so that cyls number 4 and 5 are open. Then weld the divider. That will help in pairing down the common area from 4 to 2 cyls and will help in scavenging.
Roller cams are a personal and budgetary choice. While they do offer advantages over a flat tappet, it still comes down to preference and budget.
Hope this helps.

 

Thanks for taking the time to responed with your input and advice. Sounds like your pretty well respected in your field. What would you recommend I fill the crossover with? (Aluminum). Have you every heard of anybody using Silica Bronze to weld the divider? What cam would you recommend I use? I have power brakes.
Thanks

 

Most fill it with aluminum. Yes silica bronze should be fine for the divider.
In order to achieve at or near 450hp you’ll need something in the low 230’s@.050. But if you put in on a 112lsa or so you should be fine otherwise.

 

thanks