Teach me everything you know about BB heads.
Racer
Joined: Oct 2006
Posts: 435
Likes: 18
From: Florida
I would also add that if an auto, the smaller port of the factory ovals coupled with the flow/velocity obtained from the bigger valves and bowl blend is going to be the best driving. I think that the only better head for this mild comp, mild cam situation would be the AFR 265/ Brodix 270. They would obviously allow a comp spike too and be less weight but definitely pricey. If I were you I would give a guy known as Wolfplace a call and he will give you great pricing on the brodix. You need to decide if its right vs the factory options.
Thread Starter
Drifting
Joined: Jul 2011
Posts: 1,697
Likes: 139
From: Syracuse NY
If the op doesn't mind digging up what engine it is, and possibly what castng head he has, the 255cc ovals can be made to support about 550 hp with just a valve upgrade and simple bowl blend. I think if you have the 820/241 casting you already have a smaller chamber at 113cc and with some milling and a shim gasket could net a decent comp ratio. The other option, though less traveled is to get the mill work done and shim, then get a good roller cam setup. The heads as they are will support 450-500hp depending on the combination for a hot streetbuild. Obviously you are not doing a dedicated build but you should be able to hit 425 if the comp is decent, and increase the power everywhere not just mid/topend.
How much shaving can I do until I have to worry about pushrod length changes? How much could I really bump compression up by?
When you say a shim, do you mean a steel shim gasket as opposed to a standard copper/fiber headgasket?
Racer
Joined: Oct 2006
Posts: 435
Likes: 18
From: Florida
Yes, machining for 2.19/1.88 and a throat plunge that needs blended in. the shim is almost half the thickness of a composition gasket. I think you can angle mill .100 safely, .125 with some care casting dependant...
1st Gear
Joined: Aug 2019
Posts: 1
Likes: 0
From: Sc
Buy the pro comp ovals have them angle milled.
Buy the pro comp heads spend $500 on them for competition valve and ob, angle mill the hell out of them you can make the chambers 100cc as mentioned before MLS steel shim head gaskets 0.20 should make your quench 0.39. Doing this will change the valve angle to 19° to 20° from angle milling...then you will have heads that cost $3000.000 if pro comp offers a 290cc- 320cc intake runner head you need that size for port velocity and volume that matches your CID abilities. Bigger is almost always not better.
Last edited by Lex Carter; Aug 29, 2019 at 03:24 AM. Reason: Spelling
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,062
From: altered state
St. Jude Donor '05
Oops...old thread
Biz must be wonderful to have to do that! lol
BTW I strongly disagree Les. Flow #s dont mean anything is a bargain.
Biz must be wonderful to have to do that! lol
BTW I strongly disagree Les. Flow #s dont mean anything is a bargain.
Last edited by cv67; Aug 29, 2019 at 04:27 PM.
Race Director
Joined: Jul 2015
Posts: 13,082
Likes: 3,399
From: SW Florida.
Mods need to set up a warning when somebody wants to reply to an old thread. Newbie had no idea what he was replying to. But as long as we are on the subject. Procomp castings are decent. Procomp valves are worth about 5 cents a lb.. buy bare castings. Put Ferria valves in them
Administrator
Joined: Jul 2000
Posts: 53,965
Likes: 6,190
From: About 1100 miles from where I call home.
Buy the pro comp heads spend $500 on them for competition valve and ob, angle mill the hell out of them you can make the chambers 100cc as mentioned before MLS steel shim head gaskets 0.20 should make your quench 0.39. Doing this will change the valve angle to 19° to 20° from angle milling...then you will have heads that cost $3000.000 if pro comp offers a 290cc- 320cc intake runner head you need that size for port velocity and volume that matches your CID abilities. Bigger is almost always not better.
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Administrator
Joined: Jul 2000
Posts: 53,965
Likes: 6,190
From: About 1100 miles from where I call home.
Mods need to set up a warning when somebody wants to reply to an old thread. Newbie had no idea what he was replying to. But as long as we are on the subject. Procomp castings are decent. Procomp valves are worth about 5 cents a lb.. buy bare castings. Put Ferria valves in them