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By Noob - 14 Years Ago
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If keeping the two-barrel on a 272 y-block is an absolute, are there any meaningful changes that could be made in the intake, heads, rockers, cam, or displacement to improve low end performance? A T-5 and a pair of rams horn are also an absolute, and an ignition upgrade is planned. Not trying to guild a sows ear, just want a good launch, a good y-block sound (maybe slightly lopy), a classic nastalgic look, and no worries. Thanks in advance for any and all suggestions, advice, and experiences. Brian
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By fairlane bob - 14 Years Ago
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Are you wanting to stay with the old style 3 /bolt stromburg or are you thinking of later style 4/bolt big2/barrel carb intake? My vote would be to find a late 2/barrel intake and there are several sizes of Ford 2/barrels and the Holley 2/barrel comes in a couple sizes too350 CFM and 500 cfm.
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By 46yblock - 14 Years Ago
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The late model 2V intake would be good. They are very inexpensive too. My vote for carb is the 1.02 venturi Autolite. They came stock on 292s but are undersized for that app. Should work very well on a 272, with better throttle response than a 350 Holley. The '57 and later dist. would also need to be used.
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By Grizzly - 14 Years Ago
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Noob, Are you building an engine or just tarting one up? I have a 56 272 with a holley 7448 350cfm, Pertronix in a later dizzy, and dual exhausts. The carb is nice and well sized for the engine. If I were change anything it would be to either add the metering block with the air bleeds. http://www.circletrack.com/techarticles/ctrp_0303_holley_carburetor_tunable_metering_block/viewall.html I also could do with timing improvements (do a search of the site) But it runs well for an older reasonably standard motor and will do me nicely until my build. Cheers Warren
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By LON - 14 Years Ago
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Brian , A few years ago I had a 272 +.040 ,little 25/65 cam ,pertronix ignition,Reds headers ,full balance ,350 Holley.Behind all this was an 11 inch clutch & pressure plate ,Top Loader & a 3.700 rear end in a 57 Aussie Mainline ute .Wish I could have kept it ,but you know the story ???? On a dyno it put out more HP at the rear wheels than a 302 w/4BBL .The guy who owned the dyno couldn't believe it ??? It was a great combo that really worked well .Yes ,it could have had more cam & more carb ,but I think it would have lost its driveability . Lon PS .It also blew the doors off a 65 C%#V ,327 w/4BBL at three sets of lights one night ,much to the disbelief of the scrub owner ?????????
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By Noob - 14 Years Ago
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Thanks fellas for the replies. Bought a cheap tired runner for mock-up and sorting on my `56 F100 project... will rebuild this winter while other stuff's out for paint. I wanna keep the 3 bolt (aka, 94 series?) two barrel, and that pretty much limits the intake... would any tweeking of the runner-to-head fitment be meaningful or simply good manners? Upon rebuild, a good balance and +.40 sounds good to me... just wanting to be sure displacement doesnt outstrip the motor's ability to breath. I assume a high-lift rocker set and a mild cam (is a 25/45 considered "mild"?) would be appropriate and some help in the breathing category... cfm should then be the only limiting factor, right? I have a "spare" MSD dizzy as well as a later model y-block dizzy fitted with pertronix module. So, any further ecommendations then on cam spec, use of high ratio rockers, intake runner to head tweeks, or anything else I might be overlooking... the carb is really the only constraint. Thanks again for any continued advice... Brian
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By Hoosier Hurricane - 14 Years Ago
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As long as you are boring the block, you may as well take it out to 3 3/4", 292 size. Pistons are probably easier to find than 272s also. The increased displacement will give you more low end torque, but will probably struggle to reach high revs with the small 2 barrel. You won't need so much cam since it will be limited to about 5000 rpm. Sounds like you are looking to build a stock appearing sleeper!
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By Noob - 14 Years Ago
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I think you're right John re:sleeper at the traffic light... and a 292 std bore during rebuild would be practicle and compatible with the other limitations. Any thoughts on cam, or whether I should just save the high ratio rockers for my 312 T-bird build? Any meaningful improvements likely on chamber shape/volume or deck/compression? I'm trying to get this project done with few wasted moves/mods so to conserve for the next build on my bird. Thanks for any further advice... Brian
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By Ted - 14 Years Ago
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To add to what John says, increasing the compression ratio as well as using 1.54:1 rockers is always good for some additional power as well as low end response. If increasing the cubic inch displacement, then the compression ratio raises automatically when everything else remains equal. Decking the block and milling the heads can fine tune that compression ratio further. Don’t forget to work on the ignition curve as that’s an easy mod for improving low end torque. Modifying the three bolt Holley 94 carburetor so it has a true ported vacuum capability to support using the later model distributors will allow for some additional fuel economy. But simply using a recurved later model distributor with an unmodified 3 bolt carb that’s not hooked up to the vacuum advance will provide some extra flexibility in the ignition department. But be forewarned that hooking up the vacuum advance on the unmodified Holley 94 carb to a ’57 and up distributor ends up being an excessive amount of ignition advance. This is primarily due to the 3 bolt Holley 2V incorporating both a venturi and ported vacuum signal along with a spark advance valve all within the same circuitry. This works great for a properly functioning Load-O-Matic distributor (’56 and earlier) but not so great for the later model distributors that incorporate both mechanical and vacuum advance systems. Modifying this circuitry in the 3 bolt carbs so it’s a ported vacuum signal only will allow it to work well for some additional fuel economy when used with the later model distributors. And here’s a link to the carb modification. http://www.eatonbalancing.com/blog/2010/02/07/modifying-the-holley-94-two-barrel-for-late-model-distributors/
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By Doug T - 14 Years Ago
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Since you insist on using a 3 bolt 2 bbl at least be sure it is the '56 Ford carb with the 1 1/16" venturis. This is nearly 20% more flow area than a flathead 2 bbls ie 97's etc. I think there were Holley 3 bolts made for VW's called "bug Sprays" that were even bigger. As Ted says be sure to modify the vacuum system on the carb to get the proper signal to the late model dizzy or MSD. I would also take a die grinder to the sharp edges of the carb bores of the manifold. Grinding any sharp edges into rounded curves will help the downward air/fuel flow turn the corner to the horizontal flow in the manifold runner.
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By Noob - 14 Years Ago
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This is awesome input fellas... thanks. Ted's how-to article is especially helpful, cuz as I was reading the post about modifying the carb I was also thinking to myself 'I have absolutely no idea what mods that would be or who would do it'. Now I'm like the 'little train that could'.  I'll look into availability of the larger venturi model... to be honest, I'm not sure what venturi size I currently have. I feel like you guys got me going along the right path... I'll report back now and then, and will post a few pics as I can. Brian
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By grovedawg - 14 Years Ago
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I say build as much power as you can afford! Don't worry about the carb if you're only going to run a two barrel. Something will always be a limiting factor during your build- and for you it's a two barrel carb. But you can still build great horsepower with the knowledge that if later you decide to put a bigger carb on it your motor will match you in step.
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