John: Possibly this has been covered before but I've not seen it. If your new heads are installed on a 292 or 312 with stock pistons (lets assume the block is not over bored more than 0.020 thousands) in a non decked block, what will the approximate compression ratios be? Thanks.

Paul

A lot depends on the size of the engine. A .060" over 292 will have 9.75:1 compression if zero decked. If a lower CR is desired a dished piston will easily lower compression. The VS57 doesn't work that well with very low compression so best to keep it in the 9.25-9.75 range.

http://ford-y-block.com 

20 miles east of San Diego, 20 miles north of Mexico

John, The combustion chamber is small compared to the supercharger heads, what changes to head or pistons would be required to use these with a VR57 blower and what do you think performance would be?

Pete.  I doubt that I’d see any improvement in the numbers originally posted by the Cain manifold if used on the aluminum heads.  Torque band was flat and low on the ported heads that the Cain manifold was tried on and that was simply due to the runnerless design of the manifold.  But I do have plans to run that manifold again in the future on another set of ported iron heads while experimenting with some plenum dividers and different carb spacers.  All this is being done just to see if the manifold can even come close to matching the performance of some other intakes I have here.  Any information learned from this can go into the development of a true single plane intake for the Y.

Lorena, Texas (South of Waco)

Although I've never tested a 3-2 set up we have found some definite trends with Y-Block engines. We found that with 9.5:1 compression and a streetable cam a Y-Block with ported factory heads could make 1.07-1.10 ft. lbs per cubic inch. This covered a number of builds from 314 cu in to 337 cu in and 224 @ .050" cams up to 240 @ .050" cams. Intakes ranged from modified 1957 ECZ-B intakes to Blue Thunder to Edelbrock 257 2-4 intake. The 314 made 1.13 ft lbs per cu in but had 10.0:1 CR.

Ted's stock head dyno mule comes in just a shade under that and experience indicates that ported heads will only add 10-15 ft lbs to that engine.

From the testing I have seen stock ECZ-G heads are limited to 285HP +-5. A good port job can take this up to 325-360 depending on cam, compression and displacement.

Porting Y-Block heads can make a substantial difference in HP but will have little effect on torque. All testing was done with either ECZ-G or -113 heads.

To make over 365hp with ported factory heads the testing I've done indicates that the CR must at least 10.5:1 and the cam needs to approach 250 degrees @ .050". Displacement will need to be 330+ cu in.

http://ford-y-block.com 

20 miles east of San Diego, 20 miles north of Mexico

In the 3x2 testing post, Ted said that an engine he dyno'd in the past made 340hp with a 573 and that it was rich and most likely would have made more. That's why I want to see how the 573 compares. If it's near the 4v's, it'll be 3x2's for me.


Lawrenceville, GA

I don't know what size carbs Ted used on the 3-2 testing but when HRM did extensive testing of a 312 back in 1956 they eventually had to bore the carbs to make maximum power. As I recall they were using .94"s and could only make 271 uncorrected HP. When they bored the carbs they made slightly over 300.

They gave a formula for optimum venturi size related to engine size. I would have to find the formula, can't remember. It was somewhere in the 50 - 55 cubic inch of displacement per square inch of venturi range.

http://ford-y-block.com 

20 miles east of San Diego, 20 miles north of Mexico

Hi Ted, do you think the performance of the Cain manifold will improve with the alloy heads???

a couple of photos for those not familiar with this inlet.

Pete, one of the Aussie mob. Beechworth, Victoria60 F100 Panel Van, Y-block. 65 Galaxie Country Sedan 390

Air, like anything else, takes the path of least resistance. I found when testing a 3-2 intake on a flow bench that over 80% of the flow came from the carb closest to the port being tested. About 15% came from the center carb and the carb farthest away could be opened and closed with almost no noticeable gain or loss.

http://ford-y-block.com 

20 miles east of San Diego, 20 miles north of Mexico

Guy's,

Ted is approaching testing these parts the right way. When evaluating parts you must have a base where each item is tried. This is the only way to check what characteristics each part will give. Some minor tuning with jetting and ignition timing is acceptable.

As a guideline you can use the percentage gained by the heads and use that percentage 56Hp(increase)/291hp(base)  19.243% to get your peak against what was tested before with the 3x2 shootout. This peak will change throughout the rev range and should be considered point to point. 

In evaluation part for an engine build you start with an understanding, a desirable outcome and try different parts in different configurations to obtain a desired result. This is something that only top engine builder can afford for one engine not for the entire range of parts available. Not even for Y block.

We are getting a lot of information from some guys who have taken a financial risk to produce a part for something they love. 

Grizzly (Aussie Mainline)