OLDs #7 Heads
- Thread starter TURNA
- Start date
- Status
IMO, yes but you'll need to drill head holes out for the 403 1/2" head bolts plus you'll need to enlarge the holes a tad for the location dowels on the 403 block because there off a bid. 4A's have a 2" intake valves but are similar in flow to #8's. 7's raise compression ratio 1 point. Some people like BB heads, small valve or large 2.07 ,E,G,GA,K,Ka for the 403.
How rough are they? The #7 flow 195/150 untouched. About 210/170 with 2"/1.625" W31 valves with the bowls opened with a cutter, no porting otherwise. The 4A are 190/120 untouched. The exhaust port is awful and needs grind time. The big difference is the 68 to 70cc chambers on your #7 heads untouched. My 4A heads were 86cc+. That is nearly a 20cc difference! My #6 heads started at the same size. After a cut were around 65cc. The previous owner cut one head twice since he accidentally gouged the deck, that one measured 62cc. Supposedly a .006" cut is 1cc, so I assume they did .020" cuts. You may be around 7.5 to 1 currently unless they decked the block a bunch. The cast pistons could be .040" in the hole. I believe the exhaust spring pockets are a different height due to rotators; I believe on those #7 heads.
I hear you. My guy went above and beyond on my last set of heads. There was even more work done than he thought. I said my interest in them. He held them for 2 weeks with no money down, actually took the posting down. Totally rebuilt heads for $400 up here with extras like positive seals and drilled for 1/2" bolts is a steal.
Back in the day, I was always buying half done projects. I picked up a 403 block already machined 30 over and pistons. I did have it a line honed and put one of J&S halo girdle on it. I put stock #5 one angle valve job otherwise stock heads. Holley Street Dominater (wrong intake, that Baby loves RPM's) nice reworked Quadrajet cam was like 0.496/0.512.
1981 Regal it ran 12:90's @105.
it would have run better with a Preformer. It was a fun car.
1981 Regal it ran 12:90's @105.
it would have run better with a Preformer. It was a fun car.
- Status
Similar threads
