Recommend a tunnel ram/carb BBC

[Little Mouse]

If my memory still good sbc head runner 5 1/2 inches long. The runner length all equal on the offy 7 inchs long. Thought about keeping exact same taper and extend the runners say another 1 1/2 inches then raise the bottom of the floor of the plenium up to match low part of runner. Then do new top raising up roof of runner a bit trying not to increase its volume much. Then mount holley carbs same way one reversed same as was on chevy cross ram. Of course i want good performance out it not just looks factor. But for me i love the look of the staggered holleys with one reversed. Trips my trigger in looks and was originally bought to go on no hood street rod that i never did.

[MadBill]

Yes, love the look. I put a factory cross ram system on my '70 -1/2 Z28 in '72. Had to cut the motor mounts 3/4" and build a low profile cowl induction aircleaner to get it under the stock hood. The induction noise at WOT below ~ 4,500 RPM when it came up on the cam sounded like a drowning rhinoceros...

[Little Mouse]

I tell myself there are more reasonable manifolds to do, but it always comes back to the staggered cross ram look, just great eye candy to me. My first bite into any performamce was a new 69 Z/28 and even though was not really quick nothing like the scream of sbc its the poor mans ferrai.

[Skeezix]

Was the CR ever determined, or even guesstimated with a bore-light?

Too much $$$$ involved to be ready to cut so many corners.

Get the CR.

Seems this is an "if this/then that" exercise in speculative presumptions, w/out even this foundational spec.

And 62 is hardly the diapered-Geezer oldddddddddddd frail Mr. Magoo zone.

[F-BIRD'88]

Consider using 2 eddy 650 AVS2 carbs #1905 on your Offy sbc cross ram. The 2staggered carbs are mounted side ways on the Offy carb top so that the primaries point in. The Chrysler Max Wedges were like this set up. It will do what you want very very well.
It is a modernized streetified version of holleys on the Z/28 crossram. Except run nicer. Yes they are not holleys. It will run better and meet or exceed the holleys perf. You can have your cake and enjoy it too, in a modern practical way. It will scream too.
What year Corvette? Manual trans?/ Automatic? This you CAN do. And do well.

The 2x4 Street Demon carbs with the Google Valve secondaries is another choice for this. Again carbs are sideways ,primaries pointed in on the Offy manifold.
A single Carter #P4070 72 GPH electric fuel pump will supply either 2x4 carb setup. No pressure regulator is needed.

[Newold1]

Curious what Crusinartvette and his buddy think at this point. Nice listening to some of the bantor here sometimes but the shouda, coulda and woulda is getting a bit much on this post.

What is the OP thinking and doing??

[Little Mouse]

Cruisinartvette on corvette forum along with me i had 4 vettes when younger going to buy another. F- bird88 consider an afb edelbrock inferior carb to holley no reason to use one. I can even get a holley or its copies with annular boosters all 4 barrels not wait for the Avs 3. Buy a new street demon any day of week before an edelbrock. Owned 4 cars 2 pickups QJs but with all the adjustabilty put into holleys today and can be bought new with easy parts availabilty no need for a QJ anymore. Holley owns the street demon.

[F-BIRD'88]

The 650 AVS2 is not a AFB. A better carb for the Offy Cross Ram on the street than holleys. I work on both.
I build custom holleys. The AVS(2) carbs are easy to tune easy to deal with. Learn a few new tricks. This can work real well for you. Better overall and a fraction of the price.

[Little Mouse]

I can put an annular booster holley on it have far better carbs. Chevy through that junk in thrash 1966 they were junk then still are. If the guy wants patched up afbs on his car he has his reasons wont bother trying to talk him out of it his decision. Adding a 1969 holley annular booster should help the junk some but its still a junk carb. Even chrysler threw the pile of junk in the trash did the thermaquad.

[Little Mouse]

I can put an annular booster holley on it have far better carbs. Chevy through that junk in trash 1966 they were junk then still are. If the guy wants patched up afbs on his car he has his reasons wont bother trying to talk him out of it his decision. Adding a 1969 holley annular booster should help the junk some but its still a junk carb. Even chrysler threw the pile of junk in the trash did the thermaquad.

[F-BIRD'88]

You can lead a lil mouse (stuck in the '60's) to water but you can't make him drink.

[Little Mouse]

Designed junk was moved on from by chevy 1960s and chyrsler early seventies. Anyone living in past is F-bird88. Rather sad they had to use a 1969 holley design trying to fix the junk. Now your promoting to eveyone come get your holley booster edelbrock. If the carb was ever any good then why the holley booster ?

[Little Mouse]

The original chevy cross ram and its offy copy have an enormous amount of plenuim that cant be fixed without remaking of the manifold. No just bolting any carb on it is going to fix that. It can be bandiaded but not fixed. Qiuck fuel has some annular boosted holley copy carbs in smaller size. Only holleys bigger carbs get the annular booster offered in them.

[F-BIRD'88]

Holley did not invent the annular booster.
Ya ypy can do a lot with the plebum volume and more important fuel direction to improve distribution.
The plenum volume is more of a throttle responce problem. Filling in spme of the plenum helps. Manifold heat helps.
Carb mounting orientation helps. Like the max wedge cars.
Lots of things help including using a better booster on a bettervmore street friendly carb that does not overcarb when slamming open the throttle from low rpm.
The AVS2carb does this very well. And easily adjusted too. There is much yoy can do starting with a street carb with a better booster at a very affordable price and a ton of adjustsbility.

[F-BIRD'88]

The modern well matched to the job street cam you use rather than the Z/28 or the off road cams of the day will make a big difference too.
These is lots you can do. With that manifold you are going to need to be a bit sharper than the average bear.