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Discussion Starter #1
I have a 427 BBC and i was thinking about getting aluminum heads for it. I plan to build a 572 in a couple years so if i use bigger heads that would work well on a 572 will they screw up my 427. I was thinking Brodix with 2.3 intake and 1.86 exhaust, 300 cc port size runners and 119
 

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300cc will be small for a 572.
 

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It costs about the same to build a 427 as a 454.I wouldn't waste money on the 427 and engine size dictates port runner size along with intended use and rpm range.The better use of the of money would be a 468 or 496.
 

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Discussion Starter #4
So I should just keep running my 427 with the iron heads and not upgrade to aluminum if my plan is to build a 572 in two years. Basically the right heads for a 572 would not work right on a 427, correct?
 

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Which iron heads are you running now? Closed or open chambered heads?
What plans do you have for building the larger engine?, new block of course and what is the intended use? I'm sure you can cross over some of the parts like the water pump, oil pan if enough capacity, starter and so on. What are your plans for the 427?, will it get bagged up and saved or sold?

I'd you go with alum heads, keep them small and don't get crazy in cfm info. What kind of car are you running also? Is it heavy?, TH400, glide, Trans brake!!!! The alum heads will shave some weight off the front for sure, and you will pick up performance with the right heads for your 427. How quick now and how quick do you want to get???? Lots of different ways to get the same result.
All jmo though...:cool:
 

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Discussion Starter #6
Which iron heads are you running now? Closed or open chambered heads?
What plans do you have for building the larger engine?, new block of course and what is the intended use? I'm sure you can cross over some of the parts like the water pump, oil pan if enough capacity, starter and so on. What are your plans for the 427?, will it get bagged up and saved or sold?

I'd you go with alum heads, keep them small and don't get crazy in cfm info. What kind of car are you running also? Is it heavy?, TH400, glide, Trans brake!!!! The alum heads will shave some weight off the front for sure, and you will pick up performance with the right heads for your 427. How quick now and how quick do you want to get???? Lots of different ways to get the same result.
All jmo though...:cool:
Right now GM performance open chamber. The 427 is 13:1 and burning C12. I`m running 2400 lb vette with a ATI supercase glide with transbrake. Right now i`m running 10.24 at 131 mph and would like to get to the low 9s or even high 8s with this car.
 

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I would build you a set of RHS 320 castings for your project. They will fly on the 427 and can be upgraded with more valve and work for the bigger motor at a later time.
 

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dont forget that the heads made for the larger engines have the valves spaced apart further if the head has a larger than 2.250 vallve, .. it is possible that it will HIT the cylinder wall when opening the stock block usual maximum boresize of 4.375"... where as a common aftermarket block is 4.400 boresize and larger...
 

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You just gotta know the bigger the intake cc gets on a smaller c.i. engine,the more narrow the power band gets moving it up the RPM range and the bottom end of it goes away.
 

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Question.Is the rest of this 427 set-up to spin higher?. How about the car??. Cert for faster than 9.99??. Are you going to change the T/C so you can spin the 427 up for a bottom end??. Have you considered the possibility you could spend money over the costs of the heads just chasing it trying to get bigger heads to work and then it being all wrong for the 572?. The more direct route would be to buy a set of bare ported heads from AFR or Brodix for the 572 and then spend money over the next two yrs filling them up with your choice parts.But not putting them on the 427,just have them set-up ready for you when you build the 572.
 

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Right now GM performance open chamber. The 427 is 13:1 and burning C12. I`m running 2400 lb vette with a ATI supercase glide with transbrake. Right now i`m running 10.24 at 131 mph and would like to get to the low 9s or even high 8s with this car.
I was running a 427 +030 over 13.1 with canfield heads 310 port with 2.3 valve on 2650 lb car went 9.50/9.40's stepped up to a 511 cu. with same heads and been 8.77. at your weight you shoud go low nines with a good 310/320 head and cam to match!
 

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I was running a 427 +030 over 13.1 with canfield heads 310 port with 2.3 valve on 2650 lb car went 9.50/9.40's stepped up to a 511 cu. with same heads and been 8.77. at your weight you shoud go low nines with a good 310/320 head and cam to match!
That's a good data point! I am mulling over something sort of similar but in a different order. I have some as-cast 320cc Patriot heads, but am starting over with a new short block (but reusing a good 4" crank). I may go for a 4.500 bore and do some porting on the heads.
 

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So I should just keep running my 427 with the iron heads and not upgrade to aluminum if my plan is to build a 572 in two years. Basically the right heads for a 572 would not work right on a 427, correct?
pretty much yeah...two years is a long time....you may change your mind a lot more...however is you're okay with 50 cents on the dollar you could buy some now for your current app, sell them and upgrade later...
 

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Man if you are looking for a pair of aluminum budget heads, these may do the job for ya. Yea, yea, they are import heads but these appear to be some bad ass import heads. Again, just passing this along as a thought. Since I have about three or four extra marine blocks just hanging around here I may end up building myself a budget 496 and use a pair of these just see how much power and reliability they are good for......

http://www.ebay.com/itm/Chevy-BBC-3...inum-Cylinder-Heads-124cc-345cc-/331203715393
 

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Right now GM performance open chamber. The 427 is 13:1 and burning C12. I`m running 2400 lb vette with a ATI supercase glide with transbrake. Right now i`m running 10.24 at 131 mph and would like to get to the low 9s or even high 8s with this car.
This also is a good engine build to toss on some nitrous,:cool: say, a 100 shot that should put you into the 9's right now, or get greedy and spray 200 and go 8's!!!!!!! Just sayin:smt102:smt102:smt102

I run high 8's in a 3525# tug boat and a little 505 bbc so I would just about bet a 100 shot will put you in the middle of 9's. Just a thought....:cool:
 

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Man if you are looking for a pair of aluminum budget heads, these may do the job for ya. Yea, yea, they are import heads but these appear to be some bad ass import heads. Again, just passing this along as a thought. Since I have about three or four extra marine blocks just hanging around here I may end up building myself a budget 496 and use a pair of these just see how much power and reliability they are good for......

http://www.ebay.com/itm/Chevy-BBC-3...inum-Cylinder-Heads-124cc-345cc-/331203715393
345's are 572 size heads..............:rolleyes:
 

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Actually I do know.So cut the B.S. You would have a power band start at what??. Do inform all of us of your vast knowledge of A/F dynamics.
 

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Actually I do know.So cut the B.S. You would have a power band start at what??. Do inform all of us of your vast knowledge of A/F dynamics.

So you are to here to say that those heads wouldn't work on a 4.60 bore block with a 3.75" stroke crank in a 2400lb car???


Oh wait, I forgot who I'm speaking with......"Captain NUT" of Yellow Bullet.....
 

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Still waiting for you to explain it.... or for a 496 would a head in the range of 320's work better??.
 
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