I have a straight six that with some voodoo magic I glued a Quadrajet carb to, It's on an offenhauser intake. But what I was wondering was if anybody had ever done this before. If they liked it or any problems they ran into with it. I realize that I am over-carbing my engine but I leaned out the secondaries and the are vacuum secondaries so they just shouldn't open. Basically I think it looks really cool and while I also have a holley 500 cfm 2 barrel it think the 4 barrel has a bit more wow appeal.
1) what straight 6 do you have? 2) Describe how you "glued" the quadrajet on. 3) Yeah, he beat me to it: http://www.adclassix.com/ads2/66pontiaclemansprint.htm Also, i think the incomparable John delorean came up with the timing belt concept.
3) Yeah, he beat me to it: http://www.adclassix.com/ads2/66pontiaclemansprint.htm Cool ad, not a 66 however.
Devin did it a decade earlier. http://devinsportscars.com/BeltDrive.html I don't know what you did to "lean out" the secondaries, (change rods, change spring tension?), but the primaries are small and the secondaries are vacuum supply as needed so it's fairly impossible to have too much carburetor for the engine. If it doesn't need the secondaries, it just won't use them, thats all. I'm running one off a 350 Z28 on a 262" SBC. and it works fine. Whatever you changed, you might want to change it back and see how it does.
It would actually be a good carb. Quadrajets were designed to run on the two small venturis and the rears would open as demanded. Yes, it will take some calibration and setup but it will deliver good performance and also good economy. The guys who degrade quadrajets are the guys who don't know and understand them. There are some Holley guys who don't get too upset about what size engine beat them but get mad as hell if it had a quadrajet!
a friend of mine put a 4 bbl on his 61 250 inliner, but he also had 292 pistons put in it and a bigger cam so it evened it out
Back in the mid 80's Mercury marine had a 230 CI 4 cylinder, based on a lot of 460 Ford parts. The hi po option from Mercury came with a Quadrajet.
I ran one on my '65 Chevy II 30 yrs ago. It was a 250 w/194 head, Berry regrind cam, QJet off a Pontiac OHC Sprint, HEI, headers, and a 4 spd. It worked very well. I liked it better than the Holleys and Carter AFB's I tried. The Qjet has the smallest primaries, which is what you are driving around on mostly anyway. GM actually used the front half of a QJet (2 Bbl. M2MC/M2ME/E2SE) on even smaller engines like the 229/231 V6's as the standard configuration. Did you say you changed the secondary rods or the hanger? As far as jetting goes, have you actually checked it (O2 sensor, data logger, whatever)? I'm going from memory here, but it seems to me I actually richened it on mine, which would make sense with the addition of headers.
What I mean by "glued" -I actually used a 2 barrel adapter for a quadrajet intake,turned it upside down and with some customizing and cutting I got it to work. I had to create a new throttle rod. I meant to say I leaned out the primaries not secondaries. Now I also have a set of headers that I bought from the Hershey PA swap meet. but I have had some clearance issues. The Engine is a 250. I also have a 194 sitting in my shed are there any parts I SHOULD use off of that block? I believe it would up compression using the 194 head but also limit air flow. Are these correct? Also something I have wondered for a while,while I knew that the Pontiac OHC engine had a quad-are these the same blocks other wise? That is are the Chevy and Pontiac the same.
Grab the 194 head and build it. The smaller combustion chamber will boost your compression. Do a web search for 'lump port head'. Port it, install the lump port kit, bigger valves,etc. Get a suitable cam and HEI and you should be on your way. While the Pontiac OHC was derived from the Chevy, only the crank, rods, and pistons are similiar. The Pontiac block is a completely different animal, with the BOP tranny bolt pattern on the back. You can't easily mix blocks, heads, or intakes across the two engines. More Pontiac OHC info: http://www.webrodder.com/article.php?AID=335&SID=60&CID=15
I actually already purchased an HEI but the car for whatever reason didn't like it. I know it's a simple install but it brought around a buncha bad luck so I sprung for one of those Ignitor setups that I always frowned upon. But with the price of breaker points jumping from at most five dollars last year to nearly twenty this year I figured what the hell. I have looked into the Lump ports but have been a bit hesitant - I have never done Headwork in the past and am a non believer of having work done for you that you could do for yourself. I just need a bit more learning. I bought Leo Santuccis straight 6 guide and am working from there. I would really like an aluminum head but that a bit costly and out of the question.
Get a lump port kit and scrounge up a junk head to practice on. Once you get it down pat build your 194 head and swap it.
I have found with Dyno testing and flow testing, the 194 head to raise compression is a waste of effort and will produce less power than using a lower compression head. Go to bigger valves, porting the head and install bolt in lumps. Tom
That's good info. What size valves work the best? What if you're working with a 250 instead of a 292?
look to see if the rear needle hanger moves up and down when you manualy open the damper valve [looks like a choke flap]. if it does not the plastic cam that actuates it has broken and crumbled out. this will cause a severe lean condition in a qudrajet, throttle plates open but with no movement of the needle hanger, no enrichment.
Valve sizes for intakes of 1.84-1.94 work great. For exhaust use a 1.6. The problem with the 194 high comp head is the valves get shrouded by the chamber walls.
I have a Quadrajet on the slant 6 in my Barracuda. See Slant Six Quadrajet Upgrade for more info. It works well and I like it a lot better than the AFB I had on it before. Inline engines need intake manifold heat.
------------------------------------ The Pontiac OHC-6 blocks aren't the same but are similar. Being OHC, the Pontiac blocks don't have any provision for a cam in the block and the distributor and oil pump are diven externally by a "gear & shaft thingie" driven off the OHC timing belt. They are similar enough though, that with work, some tricks and creative parts swapping,, some guys have managed to fit 292 Chevy cranks into Pontiac OHC 6's, to build stroker motors , although I'm not sure what exactly is involved. Also,, with a bit of massaging - again, I'm not sure exactly what - the CHC 6 Q-jet intake and stock split exhaust manifolds can be fitted on a 194-292 Chevy OHV 6. 'Back in the day' - late 60's-early-70's, -a couple of local dirt tracks around here had a 6-cylinder "Bomber" class that didnrt allow headers or aftermarket intakes and the Pontiac OHC intake and exhaust manifold was a common and populer swap with the roundy-round guys running Chevy 6 s. Mart3406 ========================================
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