I recently purchased a 1955 Thunderbird 292 3 speed w. O/D.  The car is bone stock.   I have built many Ford hot rods over the years.  I haven't worked on a Y Block in years.  My plan is to remove the stock engine and put it in the corner of my garage so that any future owner can reinstall it if desired.  I have a complete 40,000 mile 1957 Ford 292 2V engine and a separate set of G heads from a 312.  A friend has a 1957 Holley pattern iron intake I can buy.  I'll probably run a single Holley carburetor.  My goal is to build a stock looking decent running street engine, not a racer.   I have a couple of questions please.

Are the combustion chambers bigger on the 312 heads?  Can I bolt them onto my 292 with stock pistons?  Any idea what the compression ratio will be?  I will be using the higher ratio 1957 rockers.  I plan to run an Isky .448 lift cam.  Will I have piston to valve clearance issues?  Should I convert this car to 12 volts?  Thanks for your help.

For the most part, there are no 312 specific heads.  All '57 engines that were not supercharged have the G heads, so your "312" G heads are exactly the same as the G heads that should already be on the '57 292.  That means that the chambers are the same and they will bolt on.

The compression ratio depends on a lot of things.  The '57 292 is about 8.5:1.  If you simply swap the heads using modern composition (rather than original style shim) gaskets, it will drop to around 8:1.  If you take the engine apart for machining, you can get it up above 8.5:1.

With .448 valve lift, you will not have piston or cylinder wall clearance problems.  You will want to check valve spring retainer to guide clearance, but you probably will not have problems there.

6 volts worked in the '50s and earlier.  From that perspective, there is no need to upgrade.  However, going to 12v gives you a lot more options for lighting, ignition, and other things.  If it was my car, I would upgrade.


Lawrenceville, GA

Good advice here. You will need a '57 and up disdributor to go with the carb. I would put a Pertronix III  and matching coil in it while you are at it. The stock transmission will be fine if you really take it easy with it. An all syncro 3 speed out of a big block galaxie will be an improvement or you could go with a 4 speed or 5 speed. The 5 speed cannot be made to look stock but sure makes it a lot more drivable. What you are planning will make a nice driver that will be fun to drive. Not a race car but very good performance.

All good advice, just a couple comments. The 57 up dizzy won't have a tach drive unless you spend a lot of money for a 57 bird unit, or find an aftermarket unit that has it. I found in my 55 I could take a 3 3/8" electric SW tach, carefully remove the bezel, grind the lip off, it will fit in the original tach housing. You'll need to grind the faceplate down and a couple minor things, but it's way cheaper than the tach drive dizzy or a timing computer. If you're interested, pm me when you're ready.

I think Mummert has a T-5 adaptor that slightly rotates the trans, and brings the shift out pretty close to the original mounting hole. I found an old shifter handle very similar to the original. Cut and welded to bolt to the T-5. Looks pretty close to stock.

Due a little search here, some Autolite carbs and one of the Summit ones seem to have a strong following for street cars.



miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ

Thanks for the advice.  I had a 57 Ford Ford Custom back in high school with a 272 and a three speed. We used to have burn out contests and that 272 always won.   Took my wife to the prom in that car.   I built a 57 Victoria years ago with a 312 6V and it ran pretty good.  Blew 2nd gear on the first performance run, of course.  The last 57 I built had a 390 FE. I've had all kinds of FEs.   We were buying complete 427 side oilers back in the day for $1,200 each in the crate.   Had everything from the carbs to the bellhousing.  Sorry for the flash backs.  I have a lot of great Old Ford memories.  This will be my last hot rod.  Just looking for that Y Block sound and a little nostalgia.  Thanks again!

With the compression going up at all the 12v will come in real handy when just starting the engine. Been there done that, save yourself some grief and do the 12v conversion.


-Gary Burnette-

There's a couple of things not pointed out yet, I don't think the original air cleaner will fit the newer carb, plus you might want a paper filter.  If you do go aftermarket, make sure you get one with a dropped base for hood clearance.  As far as distributors, good luck finding one for a 57 'Bird, I've been using a Mallory on my 55 for a few years with good results.
As far a 12 volt goes, I would recommend it, if not for cranking, for everyday ease.  Need a jump? 12 V,   Want a battery tender, 12 V is easier to find,  aftermarket radio or AC or electric wipers are all easier with twelve volts.

Don

I think Florida Phils 57 Ford 312 "6v" is for venturis not volts... Just a guess but a 57 Ford it would make sense....

56 Vic, B'Ville 200 MPH Club Member, So Cal.

The '57 Victoria that he had years ago probably is.  But the '55 Thunderbird this thread is about is 6 volts.


Lawrenceville, GA

Florida Phil:
'57 Ford distributors are easy to find IF you can do without the tach drive.  (Miker's advice above could possibly help you there.) About 5 years ago I converted my '56 312 Ford to a Summit 
Racing Holley on a '57 intake, and a '57 distributor from Rock Auto.  The distributor cost me $45 back then.  The increase in power was significant and the set up has been running well for the 5 years.

Larry