</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">Here are my set-up(s) for my 455 and 428:
Carbs: Two Holley #9776, 450 CFM, manual secondary NOT double-pumper. (These use a secondary metering plate with manual butterflies, not a vacuum dashpot.)
Heads: Large valves, open chambers, Ram Air IV intake ports, ported, gasket matched, 3-angle valve job. (455 = #7K3 & 428 = #64)
Presently on my 455, I run the two carbs BACKWARDS. Sounds strange, but it works great - and it was the only way to clear the waterneck with a pair of Holley cabs. I made my own custom linkage that moved the throttle action to the passenger side of the engine and operated the carbs in reverse. They are not progressive from carb to carb. As soon as I put my foot into it, I am running on 4 Barrels. No wonder I only get 8 MPG.
A duplicate of this 455 set-up will go onto my 428.
My "new" 455 set-up will be two of the same Holley 9776 carbs, converted to double-pumpers, oriented face-to-face. To accomplish this, I have moved the two carbs to the rear by about 1/4 inch and come up with another set of custom linkage that operates the two carbs in synch. I also shaved about 1/8 inch from the fuel bowls of each carb. Half of that shave was the "Holley" logo!
I have been toying with the idea of trying out an Edelbrock P-65, but more than one source have mentioned that the Offy is a superior manifold. I would like to try Dual Q-Jets on the P-65, as I have already set up my 3rd Offy to run this way. (Dual Chevy Q-Jets face to face, slightly skewed so that the fuel inlets don't bump ...)
The performance from my 455 with the dual Holleys is incredible. I recently switched from #670 heads to #7K3 heads. After getting the jetting almost right (I still have some tweaking to do on the secondary side), I can hardly feel a difference, even though I dropped the compression by 2 points. There is so much throttle response with this set-up.
I have never tried Carter or Edelbrock-style AFB carbs. I owned a Mopar once, and that was enough to keep me in the GM family forever.
Q</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">Ok, I have the 455 with two sets of large valve heads, (061/62). The 62's (72-75cc) have screw in studs I'll probably use them. Although the compression will probably be to high without octane boost. Next I'll be looking for an intake. Happy motoring
Those are supposed to be good heads if the studs are replaced with screw-in studs. I think they are similar to the 670 in flow, but with a more "modern" combustion chamber - like the later Ram Air 3 and 4 style. Largely ignored, probably because they were not used for Ram Air I heads in '67. I have always wanted a set of those to compare to my #670's ... which I just sold.
Have you had any work done to to them?
You will probably be dealing with racing gas if you don't open up the #62's a little bit.
. . . Still undecided on which heads to use. As I remember the 061's have a cleaner/smoother combustion chamber than the 62's. I'll have to pull them back off to look again. They are supposed to be the same cc (72) or close. The 62's are bare, no valves etc. No work done yet to either set. I'm wondering if octane booster on super unlead would help at this comp. ratio ?
I never tried octane boost, so I'm not sure. I used to run 101 and 105 octane until I switched to 7K3 heads. Now I run on 91 octane Super Unleaded and me and the car are happy campers.
For what it's worth .. and remember, when it comes to free advice you get what you pay for ... If you have to use one of those two sets of heads on a 455, try to find some way to enlarge the chambers on your #62 heads. Open them up to about 90cc if you can. That's a lot of unshrouding around the valves, cutting away all the sharp corners and opening the chambers up all the way.
Ten years ago I was right where you are, looking to put 72cc heads on a street driven motor. I even had them ported and opened up to about 84cc hoping it would help. After driving the car that way for a few years, I started looking for new heads to drop the compression.
Anyway ... that's my $.02 worth. (Can someone PLEASE tell me why a typewriter has a "cents" symbol buy my friggin computer keyboard doesn't?)
I'll be watching that auction close. Thanks. Is that intake the same as yours ? Why the splits on the driver side ? You said you cut yours down 1 1/4. Was that for hood clearance ?
I never did figure out why they cast it with those two slots there. Yes, this is the same as all 3 of mine. I cut mine down to get better low end response. I don't race my car, so I wanted all the torque I could get for street driving.
I'll watch it, too. Just as an idea, it should go for between $150 and $200. Any more than that is just too much. If you plan to run your heads with the exhaust cross-over open, make sure you get a good picture of the bottom of the manifold before you bid on it. Look for any cracks around the heat passage. The Edelbrock P65 is notorious for them; I've never seen one on an Offy - yet.
Do you think I would have hood clearance problems with this man. and low profile cleaners ? I see P.A.W has a low profile Offy dual q pt#OFF-5499. I've been considering it also. Anyway I'm just now planning ahead for this setup. If I come across a good deal on parts I'll buy but I'm trying to focus on getting the thing rolling again in case I have to move soon. (selling the house). Thanks, keep the ideas coming.
The low profile Offy manifold has been on back order since 1988. Try it and see, though!
If someone can measure from the inside of their hood to the top of a stock manifold with no carb on it, I can do the same and let you know if there would be a fitment problem with the taller profile Offy. I am GUESSING that there would be a problem unless the air cleaners are really low profile.
(Take two empty toilet paper rolls, put one inside the other by putting a small crimp in it. GENTLY close the hood. Open the hood and measure the height of the two rolls.)
Q, How about if you measure the clearance you currently have and add back in the 1 1/4" you cut off the manifold. That should be close. I would sure appreciate it if you have time.
I have a slight problem. The 455 is in my GTO. The 428 is in the garage, not inside a car. I have no way to get you the right measurement. What I planned to do was measure the drop from the hood to the Offy in the GTO, then swap in a stock manifold and repeat the measurement. The difference would be the height difference, naturally, then I was going to add in the 1-1/4 inches. But I still need the measurement from the hood to the manifold inside the Bird. that's one I can't get at all.
</font><blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr /><font size="2" face="Verdana, Helvetica, sans-serif">What can I do to help you? Pete</font><hr /></blockquote><font size="2" face="Verdana, Helvetica, sans-serif">You mentioned that you have a dual quad intake. I'm trying to find out if I would have hood clearence with the dual quad intake we have been talking about here on my firebird. Is yours on a Firebird ?
I can measure a stock intake against the high-rise Offy I have. It shouldn't be too hard to come up with a measurement from the top of the carb surface to some other meaningful position on the intake, like one of the bolt holes where it bolts to the head. I'll try it tonight.
That's an idea. At least I can use that as a general baseline. Even just the height of yours plus the 1 1/4", I can compare that to the Torker I have that I no fits under my hood. Thanks. Nobody else on here runs dual quads ?
Just as an idea, it should go for between $150 and $200. Any more than that is just too much. If you plan to run your heads with the exhaust cross-over open, make sure you get a good picture of the bottom of the manifold before you bid on it. Look for any cracks around the heat passage. The Edelbrock P65 is notorious for them; I've never seen one on an Offy - yet.
