Someone else had a post like this not too long ago. Id say there are better heads out there to be used these days.

 

Old school heads. Id look elsewhere.

 

They are not a bad head and like nitrous. What head? B or P The B is what you want.
We have ran them with good results. The intake on the B head is tough, the only intake that bolts up is an Brodix 1200-1201. they need alot of work but so do the rest of the intakes for that level.

We also run spread exhaust. Pistons and Intake, maybe headers. the head can have a decent cross section. Some are valve limited, 2.150 or 2.20" depending on valve spacing.


Feel free to PM me.

 

It really depends on what they are. The -12 has been thru a few changes since 1989 when it was released.... not mention the custom roll overs and such type work many engine builders have done. Some of the real early ones are totally different than what you can buy today. There have been 3 different valve spacings over the years.

We ran them all thru the 1990s on dirt late models. In the late 90s early 2000s we started phasing them out for the 12x12, then the GB series Brodixs and some SB2.2 Cup take offs.... but by then we could make almost 800hp in ovaltrack trim with them. Good -12s are Well capable of over 800hp in a drag application.

Most of what you find in used -12s for sale today is used up junk from dirt cars so be careful about what you buy.

Shaft rockers, .180 offset lifters, custom pistons. We always ran the Brodix 1200 or 1201 intake.... and those require a shit ton of port work.
Will

 

It really depends on what they are. The -12 has been thru a few changes since 1989 when it was released.... not mention the custom roll overs and such type work many engine builders have done. Some of the real early ones are totally different than what you can buy today. There have been 3 different valve spacings over the years.

We ran them all thru the 1990s on dirt late models. In the late 90s early 2000s we started phasing them out for the 12x12, then the GB series Brodixs and some SB2.2 Cup take offs.... but by then we could make almost 800hp in ovaltrack trim with them. Good -12s are Well capable of over 800hp in a drag application.

Most of what you find in used -12s for sale today is used up junk from dirt cars so be careful about what you buy.

Shaft rockers, .180 offset lifters, custom pistons. We always ran the Brodix 1200 or 1201 intake.... and those require a shit ton of port work.
Will

We use a set of -12P heads that have been worked over some and upsized to 2.15 valves. But they are older castings (1993) and through the years have been valve jobbed and decked enough to make them "touchy" with little room for more improvement. With 12.9 compression on a bracket racing type build 420 small block they show about 750-770hp at the dragstrip on a good air day.

How much better were the 12x12's than the -12's? Asking about the non RP version... like weldtech 275, 286 or 296

To the op... do you need 850 n/a?

Scott

 

Can't edit now - but our heads were either done by Clements Porting Service or by JDS Induction (Denny Schmidt). It was well known in the ovaltrack world that the Weld Tech CNCd versions would not run for shit without a lot of additional work.
Will

 

not shure which head.the guy that has them is a big outlaw radial racer.he has a few cars and ran a similar set on his blower mustang.bought these becuase they were better and ended up sitting on them.comes with TD rockers.he said tommy kirk was going to use them on his motor but ended up a different combo.I want to use them in ultra so its a nitrous jet limited deal.421 inch motor .if I can make 850ish I'd be happy.

 

Jeremiah,

Long story, but basically the final decking and resulting porting work enlarged the chambers to 63cc and we already had a set of +2cc shelf pistons. The compression just happened to fall there and we weren't willing to spend the money on a custom set of pistons. Heck even the ring package isn't anything special. Probably some good gains to be found in getting the compression up and one of the better ring packages. I don't see 900 happening though... not with this set of heads anyway.

Scott

 

Sounds like that things needs an 8:71 on it

 

That would accomplish the power and compression.

Scott

 

That is what we in da "biz" call a win-win!

 

I'm not sure what power level I need.the ultra class has a few in the 5.0s and will Probally be a 4.8-4.9 class before ITE over with.I have to run a plate and a 4150 carb at 3250lbs. I'm assuming 800ish and the 350-400 on the plate would be good for low 5s.4s will Probally need 900ish

 

b willimans, I know of a person making 870hp with the RP version of the 12x12's. Don't know much about the other versions. Also know of a engine with the GB heads you brought up. It was making about the same power. Both engines are bigger small blocks and methanol injected but conservative cams in the lift department.

Were your -12's rolled to 12* with the moved spark plug? Mine are not. So maybe a set of the non RP 12x12's could be a decent improvement if I were to stumble across a used but unmolested set.

To the op, besides my engine I know of a couple other -12 headed engines that made similar power (maybe a bit more) to mine. But none of them were in the 850-900hp area. Than again they didn't have major work like welding the spark plug hole up or rolling 3*. They were basically the "B" version of the head with a little touch up work.

Scott

 

Yes after 1993 or so all of our -12s were modified in this manner.

99% of my experience with these heads is in Dirt Late Models so we don't make the peak power numbers that are possible in a drag engine application.

With oval stuff there are/were big weight breaks for under 362 cubic inches.... handling and powerband are far more important than raw HP.

These are also engines that have to run 50-200 laps a night for an entire season with nothing more than valve adjustment and oil changes. Very mild cams.. like 268/276@.050 and .730 lift towards the end.

In 1989 we were making an honest 680hp on a 358 with 15* -12's... Which was a big jump from the 23* stuff which at the time only made 620hp... the last -12 engine we built new made 780hp out of 362 inches. The -12 head grew 100HP in an 8yr life span for our program.

Also no doubt if you throw 20* more duration on the cam and 2 carbs or injection and well over 800HP is going to happen with any of these heads we are talking about.

You can make good power with any of them but the OP is talking about heads up racing and all of these heads we are talking about carry the same weight and NO2 jet rule.

870HP out of 12X12 headed engine is a very good motor... but 870HP out of a GB2000 headed engine is kinda below average for drag racing... our late model engines made 850HP with one 4150 carb and a cast intake on gas and that was back in 2004.

The right GB's will make well over 900HP today and that is not ever going to happen with -12's or the 12X12 IMO and your going to spend close to the same $$$$ on the top end - unless you get a deal on some used stuff.

There is just no way I would build a -12 or 12X12 headed SBC when a GB headed (or better inline valve headed) engine can run at the same weight and NO2 jet.

Heck if you want to look for a deal on used stuff then even the current/recent 9* or 11* Dart and Brodix based top ends are availiable on the used market pretty reasonably... Entire 900hp 11* or 9* Alum engines (430-450 inches) are for sale fresh and turn key carb to dry sump for $25,000 and less... 3 yr old 13* engines are under 20K.

Will

 

There is a fellow at my home track with the 12x12's going 7.40 in a suspended dragster. I wouldn't guess exact numbers, but that is making some decent steam.

 

Ok, so I got burned trying to buy a used up, gutted set of -12's, and on top of that, the 2 guys handling my engine build, guessed at the cc chambers of the head instead of verifying what size they actually were. Actual was 40 vs 52 that was told to Gibtech Pistons. Now I have a set of custom domed pistons that gave me 18&1/2 to 1 cr.
So I am trying to find the most cost effective route forward, which seems to be buying a bn set of heads for my bn short block, that is a Motown block, 4.185 bore, 3.875 stroke w/Oliver rods, 427ci. Would like to get lucky and have an engine builder that has played w/the GB2200, or 2400 stuff tell me if they know they will if they might work with the piston speced for -12 head? I realize I am putting the cart before the horse ��������

 

Anyone using the Profiler 13* 219 casting 285 cc 2.180" valve heads for drag racing with good results?