My stock 1955 292 has been modified to 12 volts, '57 distributor, '57 "D" code manifold and new 465 cfm Holley.  It runs and drives fine.  I have a set of "G" code 1957 Heads that just returned from a new valve job. I also rebuilt the high ratio rockers from these heads.   I also have a set of 1957 Exhaust Manifolds from the same engine.  My plan is to swap the '57 heads and rockers on to the '55 engine.  Will I notice the difference?

Yes!  Higher compression ratio.  Many subtleties: Ted has addressed many of them in this forum; and, John Mummert's site has charts of various heads on various engines.  ECZ-G stock heads on a stock 312 has published C. R. of 9.7:1.  On a stock 292 it will be lower by about the ratio of 292/312.  Dynamic C. R.'s are lower.  Again, see Ted's various work on his site, and here.

Regards,   JLB

55 Ford Crown Victoria Steel Top

You should, particularly with all of the other changes.

Also use the '57 exhaust manifolds, unless you already have something better like headers.


Lawrenceville, GA

I have the '57 exhaust manifolds that came with the '57 engine.  The '57 car this engine came out of was a 1957 Ford Station Wagon with a 272.  It had G Heads with the high ratio rockers.   I do not know if the '57 exhaust manifolds will fit my '55 TBird.  The '57 exhaust manifolds don't look much bigger than the '55 manifolds, at least from the outside.  The '57 exhaust manifolds have the bigger manifold casting numbers.

As long as you have everything apart, you might want to 'gasket match' the heads & manifolds, and maximize the upgrades. Also what about the '57 tubular pushrods? Did they come with the rockers? Don't forget to double check valve gear geometry in case the head/gasket/pushrod height is significantly different (see Ted's YBM articles).

6 VOLTS/POS. GRD. NW INDIANA

I bought a complete '57 engine, so I have the push rods that came with the '57 "G" heads.  They are the type with two stripes at the top. I think all will be fine, but I will check the geometry. Right now I have a mismatch between the small port 55 heads and the 57 intake.  The "G" heads should fix that issue.  I'll have to leave the '55 cam in place as I don't want to pull the engine right now.

Yes, at least one of the Bird manifolds is different.  You can compare when you have it apart.  A set of '57 manifolds will help.


Lawrenceville, GA

There should be an obvious difference between '55 exhaust manifolds and the '57 units UNLESS a previous owner has already swapped exhaust manifolds.

The '55 units have rounded top surfaces while the '57 units are flat on their top surface and are much more log like.

A '57 driver side T-Bird exhaust manifold is different from a '57 passenger car exhaust manifold.  The biggest difference to the eye is that the exhaust header pipe connecting studs are clocked (turned) in orientation.  The driver's side Ford passenger car exhaust manifold will not match-up with the flange on your 'Bird exhaust pipe.

Compare the two eBay listing below for the exhaust pipe orientation on the driver's side:

'57 'Bird click the link below . . .
http://www.ebay.com/itm/1957-FORD-Thunderbird-Exhaust-Manifolds/162640037074?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649

Passenger car click the link below:
http://www.ebay.com/itm/1955-1964-Ford-Mercury-272-292-312-Y-block-V8-original-LH-exhaust-manifold-/192283716761?epid=1323122997&hash=item2cc500ac99:g:6REAAOSwBMVZcmkp&vxp=mtr

Hope this helps!  


NoShortcuts
a.k.a. Charlie Brown
near Syracuse, New York

I believe the "ECJ" driver side manifold is the one to have for a T-bird - hunting them down is sometimes a pain........ When mounted, the outlet flange is twisted inward toward the engine to clear the shift and steering linkage. 

 
 Steve Metzger       Tucson, Arizona

I saw the difference between the passenger car and Thunderbird exhaust pipe mounting flanges on the ebay listings.  Will the later style passenger car manifold fit the left side of a 55 Thunderbird if a reworked or new header pipe is fab'd?

AKA   Bob-93021