what are thoughts on a set of #13 heads for $450, I believe at this time , they are bolt on.
the seller is advertising them as RAM AIR III , which I beleive is incorrect, besides ...
thoughts....???
That's a pretty good price if they are ready to bolt on. Ram Air III heads are #12. Not sure what you are bolting them onto, but be carefull you don't end up with too much compression. I bolted #12's onto my 1976- 400 and it raised the compression so high that the motor pings under acceleration. It will not run without pinging unless I add octane booster to the premium fuel.
I'm wondering if they would be worth the trouble. I'd be bolting them to a 70 400 from a Catalina, replacing the #11 heads. that engine was rated at 8.8 comp. where as the #13 is rated at 10.0- 10.25 depending were you read.
I have a pair of 7K3 heads from a 72 GTO, book says that's a 8.2:1 head. gives you the big valves as well.
I guess if they are ready to go at that price , they might be worth putting on the shelf? for now.
__________________
later...rog
AADD supporting member !!
I'm a collector...not a builder!!Located in sunny central Saskatchewan at the lakehead!
I own a pair of #13 heads that i had on a 400 two summers ago. They are 211 /177 valve sizes and the cc rating is 72-75 depending on what publication you read. The comp ratio will be 10:2 and they flow decent. The heads came on 1970 GTO auto cars and 70 GrandPrix.
The RA IV has round port heads and the RA III has D port Heads. Both are great Pontiac heads but they are quite different. On the RA IV the exhaust ports are all 4 round as opposed to the standard vintage Pontiac where the end two ports are ovoid and the center two are D shaped. The casting numbers are on the outside of the head. RA IV for 1969 casting # 722 and RA IV for 1970 is casting # 614. The date code on the RA IV heads was on the head under the valve cover but gets drilled off during manufacture. The RA III are # 12 castings on the GTOs and are date coded. You find the 1970 RA IV heads in two varieties. The ones with 614 cast on the end port only are the original heads from the cars. The ones that state 614 and other ports have 2XC are service replacement heads made from 1971 to 1976. The majority of 1969 heads are cast with the 722 on the end port and no date code. There are however a few 722 heads with the later 2xc cast on the other ports indicating a 1971-77 production date. Although not exactly original, the SR heads are some better (more bracket mounts, better metal, the slightly better intake ports).
#13's heads are a nice high performance Pontiac D port cylinder head, 1968-70 number 16, 31(very rare RA I heads), 62, 48(RA III) , 12(RA III), 13 are all big valves 2.11 intake and 1.77 exhaust valves heads in the 72cc combustion chambers ball park. Like one member mentioned earlier, they will detonate if high octake premium racing fuel is not used unless you get your engine built properly with the right cam configuration and custom dished pistons such as ROSS... Good price for these heads if they are in good shape and built properly. 1971- 96 heads and 1972- 7K3 are 2nd best choice, same valve size and 96 cc combustion chambers, great for a 455 build up, 1975-79 heads 5C and 6X are very good heads as well they work well with today's crappy fuel, great for the Pontiac 455 top end as well, they can be ported to flow as well as the famous RA IV heads !
I agree with Pascal that your better off with the 6X heads. And if you can find them the 455 #64 heads. I'm running #13 heads on my 1970 GTO and ran on low grade fuel to Oregon and back with no pinging, yet my buddy with the #12 heads was running the best fuel and would ping on the hills
-- Edited by 455gto on Monday 1st of March 2010 05:02:23 PM
