I have a 347 Pontiac out of a GMC truck in my Modified. I'm going to put it on the road using the original single 2Jet but I'd like to do something different eventually - I know that a Tri-Power is the logical option but what's logical about hot rodding? Also Tri-Powers are not exactly easy to come by here in the UK. I was thinking I could make something like a U Fab intake and rotate the mounting flanges to work with a side draft carb. Maybe 4 HS6 SU's. A half way house might be a couple of 2" SUs on a Y adapter on top of the factory manifold. Anyone done it, seen it done or got pictures?
Six HS4s would fit in the space of three 2GCs. If you have to trouble yourself making the U-Fab type log manifolds then in for a penny, in for a pound. I'd love to see eight HS2s with the little velocity rams facing out and tilted upward...
That's a nice idea - cheap enough to buy the carbs over here. Maybe £15 each. I produce an adapter to put the HS2 on a 2CV engine and that uses the HS2 because it's the one that people with an old style Mini get rid of when they are tuning it. The linkage would be another issue - but not impossible by any means.
I never thought you'd go for it! I'll be gobsmacked. Doing a straight linkage might be a good deal easier than a progressive setup. I'm sketching a few arrangements and can't seem to find anything better than vertical bellcranks joined by a rod through their centers, each opening two carbs and in the same plane as the front pulleys. The throttle response ought to be better than okay.
Should be do-able. I plan on building an intake for a project of mine, with 4 1 3/4 SU's, on a home made cross ram intake. Individual runners, 1 carb feeding 2 cyl's. I think it's a great carb, and should work well on applications like this. If you go ahead with it, keep us informed. I may do a How-To on my intake when I get around to doing it. I've already got 2 Volvo carbs to get started!
I've seen those twin choke SU's on eBay but never managed to get hold of one - they sure are cool. Most any other SU is relatively easy to get hold of here and the HIFs are a dime a dozen - especially the 38's. Post the linkage sketchs if you can.
There used to be a Mangoletsi Intake Manifold to put 4 SU's on a Rover 3500 ( Buick 215 ) It looked pretty cool... I'd use that as an inspiration for a homemade intake for your engine.
Sorry, no scanner. Just picture a throttle shaft running parallel to cam and crank in the valley between the intake logs. It is supported on a couple of bearing blocks and has four discs welded to it, each matching up to a lateral pairs of carbs. The discs are the bellcranks, and rotating the throttle shaft causes pullrods to open the carb throttle plates. As the carbs are not perfectly aligned across from each other, one pullrod mounts to the front of the bellcrank, the other behind. Still haven't worked out a progressive linkage, though.
Found something similar at the bottom of this page: http://www.btinternet.com/~jon.wolfe/carbs_and_manifolds.htm
If you wanted to base it all on a factory 4 barrel intake manifold, I have one from a 1957, 347 Pontiac...Has the correct generator mount etc etc. PM me if interested.
Wire it with all Lucas stuff and you'll have the complete British experience Sorry, I just couldn't help it
blackjack...................when you get an idea drawn up on that linkage, let me know.......I 'prolly have some small, aircraft discard / modification , torque tubes / push-pull rod doo dads, that I will donate to the cause..........Zerk's description in post # 10 sounds doable, and the pieces I speak of are appropriate in length, ( I think), for that description................Does that sound possible, to get a visual on all this monkey motion??????
Thank you all for some terrific replies and suggestions. Tom - the 2bbl is perfect. In very nice unmolested condition and should be fine to get the car out and about. Having a working choke is a real improvement. McTim - great picture and very helpful. Looks like that's in a T too. Stealthcruiser - Yes please. I'll add you to my friend list if that's OK. Rocky - Yes please - I'll PM you. Zerk - Thanks again - that sounds a sensible method. Should look great too.
Hey that's not fair - these days NOS Lucas stuff is reliable compared to Chinese pattern parts. Who would have thought I'd get such an enthusiastic response about putting a quintessentially British carb on a US V8. However, the world's a changin' - the English soccer team came a poor second to the USA in their World Cup group. Who'da thunk it???
However, the world's a changin' - the English soccer team came a poor second to the USA in their World Cup group. Who'da thunk it???[/QUOTE] As it should have been!
As it should have been![/QUOTE] "Salt for your wound, sir?" If the match had been Rugby, all bets would be off.
Here's the pic Zerk found. Looking at some pictures of SU carbs and remembering the ones we ran on OHC Datsuns years ago, I'm thinking that they are not all created equal? The ones I remember needed a LOT of bore spacing on the manifold to fit everything side by side. (The setup I remember):
Nothing wrong with Lucas parts that a little jiggling or pounding wont fix. I could fill a page or two with the roadside expieriances I've had repairing my MG's and Triumph's but who has time for that.
Love it! The Rover V8 "X-ram" style intake is bitchen! Mctim, your friends one also looks sick. Good luck blackjack, of course keep us updated. I'd love to see thi go through.
So TRUE, and so SCAREY!!! As to the SU question; see no reason why it wouldn't work if you do your homework and use sufficiently large or a sufficient quantity of SU's. We put (4) H4's on a Ford Pinto 2.0 litre (121 CID) and it ran great. Not sure 4 H6's would be sufficient for a 347 Pontiac. Jon.
The 3500cc Rover (Buick V8) ran with a pair of HS6 carbs. I'm fairly confident that if I double up on carbs and use the same needle as a starting point I shouldn't have too many problems. Rolls Royce and Bentleys of the 60's and 70's were 6750cc (about a litre larger in displacement than my Pontiac) and ran a pair of HD8 using a BBA or BBS needle for the US market. So the next size up might be an alternative.
Part of the difference may be in the model of the carb. The HSs and HDs we've been talking about have external float bowls that take up space. The later HIF models had internal float bowls, and could probably be grouped tighter. I wonder if multiple SUs could run off of a common float bowl, plumbed to fixed jets? That would save room and be damned cool
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