You can go to a website..United Machine... It's affiliated with KB pistons and find what your exact CR will be static and putting the cam/rod specs for your dynamic ratio. You need to know about your parts, ei: head cc's, gasket thickness, where piston is, etc. I use it all the time on my racing engines.

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

Worst case if you pop the t86 you can always drop a t85 in place. The t85 was what they built the t10 design off of so it is plenty strong and comes with the r11 overdrive which is stronger. I'm no expert on y-blocks, but i've always had good luck building engines by taking a hot factory performance motor, shaking it up and running that. Mabey consider building it to 1957 2x4 spec and do some little stuff like deck the block? That's only like 9.7 to 1 from what i read and most of your old cams are pretty soft on valvetrain.

You asked if the Dana 44 was strong enough. It was stock on the Dodge Viper, so yes.
I build the 312 that is in my 55 Tbird in the late 60`s. The car has the air cooled FOM. I used a rebuild kit that included a unknown brand cam advertised as a 3/4 cam, new pistons and I used the "new" moly rings. I have a tag from 1973 that shows my compression was from 165 to 180. I have a B intake and a Holley 600 vac carb. I am using an original Pertronix 1 point replacement in a 57 tach drive distributor. Along the way I installed some Heddman headers, TryY, not later straight back ones. The hedders lasted a couple of months and the only increase I saw was to the noise level.
You do want torque NOT high RPM horsepower if you plan to drive on the road. Long duration cams kill manifold vacuum and torque. You choose. Pete

I wouldn’t be too concerned about a T-86/R10 taking the power. What I’d worry about is the shock load from side stepping the clutch. Same with the Dana rear end. IIRC, it should be a Dana 45, think of it as a 44 with smaller axles. The rear end in my bird got changed somewhere in the past, and it is a 44. Driving, yes, abuse no.

If you’ve still got the 55 exhaust manifold, they’re probably the restriction in your set up. Ted has an extensive set of exhaust manifold and header test, including the FPA’s (which is what Mummert lists). I run those, but I’m also running a 2 1/4” pipe all the way back, exiting behind the rear wheel. I think you can buy repop 57 flat top manifolds, the left side is specific for a tbird. I suspect they are fine with a stock manifold pipe set up.

I’m not a racer, strictly a street guy. I like nice fat torque curves, and don’t much care if it lays down at 5-5500 rpm. That’s what gives the nice throttle response on the street when combined with good tuning.

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

Thanks for the replies.  There are other issues to consider.  I have some experience with Y Blocks, but it's been quite some time.   Significantly increasing power strains other components in the car.  My car has a T86 three speed transmission with O/D and I want to leave it that way for nostalgia reasons.  As I recall these transmissions weren't the strongest.  Also, the 55 rear end doesn't look like it could take much abuse.   The drive shaft looks like a straw to me.  What I should probably do is build the short block stock and change the cam.  I have already upgraded the ignition with 57 Ford parts.   Would headers make a difference I could feel?

The link talks about dynamic ratio and “making my head spin”. Mine was spinning so hard it threw my back out when I was going thru it.

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

Fixed the link.


Lawrenceville, GA

I had a 9:1 motor, a 292 ( .040 over, stroked to 320 IIRC) in my 55 bird. It was a real 9:1, cc’d heads, gasket volume, etc. It ran great, but with a little boost (4 lbs at 5000rpm, just reading boost at 3000), it needed 2* retard on premium fuel. It ran an early version of Mummert’s y-270S cam, 10-12 initial, 36* or so all in. Ported 113 heads. I drove that without the supercharger, and it was a great little street motor. When I put the aluminum heads on, the ‘charger went away, and I was 10.5 or so. Took a bunch of playing with the cam to get the dynamic ratio low enough to get by on premium fuel. I should have cut the pistons when I changed the heads, or changed the pistons as I think the quench area is part of the problem. Bottom line, for a warm weather sea level car, I wouldn’t go over 9.5:1, and probably I’d stay more like 9.0.

Now, fill it up with racing fuel and put some advance back in, it’s really fun. Expensive, but fun.

I couldn’t get Charlie’s link to open, so I can’t reference those comments.



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

Increasing compression will be good, even for street use.  However, you don't just pick a ratio and hope for the best, particularly when we're talking in the neighborhood of 10:1 with iron heads.  You will need to pick the cam and then determine the static ratio required so that the dynamic ratio is low enough to play nice with premium pump fuel.

Here's a discussion on the subject.  Lots more can be found by using the search feature.
http://forums.y-blocksforever.com/Topic57116-1.aspx



Lawrenceville, GA

Hi Phil, I would build to Ford Spec. Look at the deck height and chamber volume, I think you will find the piston to the top of the block to low, I like steel head gaskets (that's only me), I do not like any Blue Head Gaskets (water stains on the sides of the block), you will find the chambers all over the place (large or small), do your best to equal them, do not depend on the pads on the sides of the heads, they may or may not be correct, the cam I like is an Isky RPM 300 (I know it's old), get a good 3 angle valve job, have the distributor run on a tester for correct advance (vacuum and mechanical)