Don Terrill’s Speed-Talk

On a 8500 rpm SBC the springs lasted 3 times as long with 20 lbs less spring pressure

CompStar 2.00 rods(csa6000cs2a2ah) have the bolts moved toward the center line, so the bolts clear every where better. Most of your rod manufactures
use 2.1 blanks( 350 journals) so your clearance is no better. I would check bolts center line, before you buy. Speedway has CompStars for $633.

very good post; two thumbs-up

Why tie up money in a block like a 509 casting; when you can buy a dart shp ( shp pro better yet) for a few dollars more. You don't have the clearance problems, thin cylinder walls or the mains wanting to walk. Also the wore out lifter bores, sell your block to someone who want a low hp street engin...

With your heads & compression your combination want to be shifted between 7000 to 7400. I am saying this because peak HP will be above 6600. Run a cam with 268 to 272 intake; with 12 degree more exhaust on 110 lsa. Your heads and compression is what's moving your shift rpm up; the cam you have w...

With .040 over bore on a 327 (4.040) a .035 to .040 compress gasket would work. A cam with 224 to 236 intake & run 6 to 8 degrees
spread on exhaust. Run 109 to 112 LSA ; 109 for a lope idle 112 for a smoother idle.

On your rotating ass. run small journal rod size ( 283 ) and comp star (csa6000cs2ah) they weigh 591g and clear a standard base circle cam.
I have ran those rods in 700hp engines with no problems. ohio crank are reasonably priced and give them your bob weight and they can balance
for you.

Dart block; shp pro or little M

On budget valves there are a lot difference in quality between brands; best to find out what alloy they are made out of. Any one piece 21-4n set would stand up to a HR spring. With afr 210 you get good components, not sure what atk is using.

From post before a .075 angle was going to keep compression the same. That would be part of cylinder head change; and would have very little loss in compression.

The 40 lbs you lose by going with AFR will lower your et .08 to .1 sec. CamKing's cam spec is close to what I would go with. Also factor in hp gains from gains from cfm & cam you should run 5.0's maybe even better.

smaller runners have less spread larger runners have more spread or carry peak hp to a higher rpm.

Smaller csa faster speeds; larger csa slower speeds.

Also your spread between peak tq & peak hp ; is a indication on runner taper & plenum volume size.

Forget about port volume; csa is what to concentrate on. A constant port velocity or as close to it is more important than the volume.