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Low rise intake BBC Intake manifolds

13K views 12 replies 8 participants last post by  Greybeard 
#1 ·
I built a big block Olds powered Corvair years ago using Toronado drivetrain. The intake is Toronado which is about the lowest rise thing you've ever seen and airfilter clearance is still very tight.

I'd thought many times that what it really needs is a 427 but have been put off by what "I" perceived to be a height issue. Last night I was over at a friends place who has an LS6 and was looking at his manifold, which is about the lowest Chevy manifold I'd seen. As the connecting rods in my Olds are over 3/4" longer than the BBC, which would mean higher deckheight, I got to wondering if I could get a BBC in where the Olds is.

So my question to you is: What would be the choices for a lowrise manfold package in alloy. Multi carbs are OK too.
 
#3 ·
Have any photos of the V8 Vair?

Would love to see some detailed pics. I have a good friend who has been searching for a nice V8V for years - he'd love to see the pics (as would I)

Dan
 
#4 ·
As you mentioned, the LS-6 Rect Port/square flange intake can be found from time to time....my neighbor sold his once I told him what it was.....

The 68 and 69 Vettes had a very low hoodline, even with the BBC hood.
The 390 horse 427 for both years, low-rise, oval port, Q-jet flange.
The 400 horse tri-power for 68-69 was lower-rise than the 67 unit....
oval port.
The 435 horse tri-power for rect port engines for 68-69 is lower than the 67 unit.
I've heard it in Vette circles that the lower intakes for 68-69 slowed the cars down across the board a tenth or so compared to the 67 cars....dunno if this is the truth... I can tell you that ALL the tri-power set-ups cost a young fortune.

The old Edelbrock Torker clears the BBC hoodline too, possibly another option
 
#5 ·
George is 100% on the money with everything above! :thumbsup:

Whether it be FACTORY or aftermarket, the LOWEST alum 4bl intakes for a BB are the LS6 intake such as used on 70 Chevelles (Holley only bolt pattern) or the 68-9 Vettes with a hyd cam 427/490hp (Q-jet only only bolt pattern). I've NEVER seen an aftermarket, alum 4bl intake for a BB as low as these. Those lo-rise alum intakes for the Vettes used to be dirt cheap, but not any more. Form personal comparrisons that I've done, the Vette alum intakes and the stock style cast iron BB intakes (Q-jet) APPEAR to be nearly the same. Thus, the ONLY advantage I see to the 68-9 Vette alum intakes is weight savings (MAYBE a little added heat disipation). Oh ya, there is also some added cool factor with the Vette alum intake. When you install a 68-9 Vette Q-jet alum intake and a lo-profile air cleaner (hides the carb), at first glance, it has the look of an LS6 engine. :D
 
#6 ·
I would prefer to go with an alloy manifold and alloy heads as this thing has a serious weight distribution problem that a bunch of Chevy cast iron wouldn't help with. 990lbs front, 2110 rear. It'll drop the horizon out of sight with little effort now. The Olds is probably still lighter than a BBC with all the alloy I can put on it.

I guess I need to see if we can measure the LS6 and get an approximate distance from crank centerline to carb flange, and get the firewall out of the 'vair (is it a Torvair, or a Coronado) and measure it. At least with my friends LS6 available perhaps I can get that measurement.

I know the deck height on the Olds is over .8 higher than the Chev, but that can all be eaten up with head thickness and port location as to exactly the height of the engine.

Tom, you mention low profile aircleaner, and I have one that's fairly low, but did you have anything in particular in mind when you said that?
 
#7 ·
How are you going to get the Chevy big block to adapt to the Toro transaxle? The right side axle shaft runs immediately under the middle main bearing on the Olds (or Caddy, in an Eldorado) because there isn't enough room to put the axle shaft under the rods--they'd hit.

You'll be having no end of problems fabricating an oil pan with appropriate clearance, fabricating brackets to support the final drive where it should bolt to the block; installing adapter plates between block and BOP-style trans bellhousing, and when you're done with all that--that axle shaft better be under the center main bearing. Which could be tough considering the BBC has MUCH huger bore spacing than the BBO; so the block is probably longer from bellhousing bolt pattern to the center main bearing.

I'd think it'd be easier to move whatever is the clearance problem on the top of the engine than to stuff in a Chevy and hope it turns out to be a more-compact package.

What you do have in your favor is the deck height on a passenger-car big block is 9.8" whereas the Olds big block is 10.625
 
#8 ·
How are you going to get the Chevy big block to adapt to the Toro transaxle? The right side axle shaft runs immediately under the middle main bearing on the Olds (or Caddy, in an Eldorado) because there isn't enough room to put the axle shaft under the rods--they'd hit.

You'll be having no end of problems fabricating an oil pan with appropriate clearance, fabricating brackets to support the final drive where it should bolt to the block; installing adapter plates between block and BOP-style trans bellhousing, and when you're done with all that--that axle shaft better be under the center main bearing. Which could be tough considering the BBC has MUCH huger bore spacing than the BBO; so the block is probably longer from bellhousing bolt pattern to the center main bearing.

I'd think it'd be easier to move whatever is the clearance problem on the top of the engine than to stuff in a Chevy and hope it turns out to be a more-compact package. What you do have in your favor is the deck height on a passenger-car big block is 9.8" whereas the Olds big block is 10.625
http://www.dynosources.com/Article_detail.asp?id=416&Section_Id=136#Worlds_Fastest_Motorhome
http://www.dynosources.com/Article_detail.asp?id=81&Section_Id=136

As the GMC Motorhome used the same engine/trans as my Corvair has, most all of the above mentioned pieces and problems have already been worked out. I've got a good relationship with Dynosources as I lived in Sequim where they are located, and anyone who'd go to the trouble of installing the Olds in the first place isn't really afraid of trying something new.

I guess I didn't make myself clear. It's not the clearance now, although very tight, it was the challenge of installing the BBC, and retaining a back window now only 3" above the carb. If I cut any more out of that area I won't have any support for the window. I've not pursued the Chevy aspect as I didn't think it would be MORE compact, but the height issue was the deal killer.

However, you made one point I wasn't taking into consideration and that was overall lenght of the BBC. The firewall is boxed for the Olds waterpump pulley, and the back of the backseat has had the springs removed and a box built-in to fit around the firewall box. The seat is in it's stock location, and unless you tried to seat 3 accross in the back, no-one would know. But if the BBC/with WP was much longer it might not work with the stock WP. Electrics, inline electric, or marine pump might solve that issue.
 
#9 ·
Funny you should post those links. I've got a Toronado transaxle/front frame and suspension parked under a tarp in the driveway--and an 8.1 core engine hanging from an engine stand in the garage.

Hadn't occurred to me to marry the two.

I still have qualms about getting the axle under the center mainbearing. You may force me to actually break out the tape measure...

Are you using the Toronado torsion bar springs? There's a guy around here who's talking about stuffing a Toro transaxle in his 'Vair to replace the 327. We measured the car, and it didn't look like the torsion bars would fit in front of the rear bumper.
 
#11 ·
Schurkey,

I used the Corvair rear suspension, built a subframe to fit what was left after the saws-all was finished. The engine/transaxel mount in the subframe and to do major work on the engine/trans I unbolt the subframe and lift the chassis off the engine like a 4th gen Camaro. Custom halfshafts connect the Toronado drive to the Corvair hubs. I'm using the original Corvair springs with airbags to hold it up. It works, but the bags are over "rated pressure" and I'm still trying to work out an acceptable spring rate. The rear coils are a single pigtail type like the rear spring on a early Chevelle.
 
#12 ·
I'm currently working on a 65 Corvair v8 project myself. Considering the price of a junk Chevelle or Camaro and the parts to restore them, these Corvairs are an attractive option. With a V8 in them they can run with the big dogs for a lot less money and show them a thing or too when the corners show up.
 
#13 ·
The V8 Corvair kits are still available and make for a quick autocrosser. My problem with them is in taking so much out of the passenger compartment that my 6'3" frame doesn't fit well. The cars are still cheap. I've located a '65 and a '66 that the owner wants $1800 for the pair. The '65 is a turbo, engine needs OH, the '66 is a 140hp that won't start. My car is suprising heavy and I've been thinking about trying something different yet. I have a 215 cid Buick engine that I want to put in a Vega, or maybe even a Chevette, but haven't found the right car. If I reverse rotate the Buick and install it in the original Corvair engine compartment, I only increase the weight of the vehicle by the cooling system, keeping total weight under 2800#. If you tossed the spare tire it'd be a wash. moving the battery to the front compartment with the radiator would give it a more balanced weight ratio.

With the weight distribution of mine, straight lines on level roads are preferred.
 
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