Oops! E-4 cam lift is .283".

.425" (read the wrong line while typing) is VALVE lift with 1.5:1 ratio. Sorry about that.

6 VOLTS/POS. GRD. NW INDIANA

According to Ted, even if adjuster screw is set at the top of it's travel (maximum lift) when geometry is optimized, then 1.56:1 (resulting rocker ratio) X .424" (E-4 cam lift with zero lash) = .441". Enough less than .500" to allow a safe margin of error, so no clay test likely needed (?).

6 VOLTS/POS. GRD. NW INDIANA

Only if valve lift is about .500" or greater.


Lawrenceville, GA

[quote][b]John Mummert (10/14/2009)



To run the best you want the piston to come about .045" from the bottom of the cylinderhead.



JOHN;



Scenario: "G" heads cut .006", new seats level with the original chamber floor, stock length valves, older repro B-2 rockers & longer tubular pushrods with optimized geometry, and E-4 cam installed straight-up.



If piston-to-head clearance is at least .045", is clay testing necessary?




6 VOLTS/POS. GRD. NW INDIANA

390 CFM carb with K&N filter

55Birdman  Hickory NC

so any one have any thoughts or ideal on my air intake system ideal

10cc domed pistons work quite well with the 471 heads.  As an example, a 0.060” over 292 with 471 heads and with the original pistons 0.005” in the hole will have a 7.6:1CR.  Same engine but with a 10cc domed piston raises the compression ratio to 8.4:1.  Don’t confuse the ‘471’ heads with the C1TE heads though as you are dealing with two different sized combustion chambers.

Lorena, Texas (South of Waco)

ok so do you think either the 270 or 284 grind from Mummert would be good choices. the 284 might be kinda rough for my application but i will be running a nv4500 5 speed so i will have a fairly low first gear and ill have relatively low rear end gears so i should still have plenty of torque.



So i will probably want to have the blocked milled untill the pistons are like 5 thousandths below the deck. and yes im assumeing i have the normal truck heads so maybe have them milled slightly to level them out and raise compression a little more. what about if i ran a set of dome top pistons would this raise compression to much to be streetable? would i need to adjust the deck height differently? im sure these are all simple question to you experienced builders but im only 18 and this will be my first motor build altho ive been around my whole life.

It can be a little difficult to get a lopey idle and not lose low end power. The lope is caused by inefficiency at idle which usually extends up the rpm range to some extent.

A narrow lobe center such 108 degrees will help the sound and can help low end. This type of cam usually works best with headers. You don't want too much overlap (when both valves are open) with exhaust manifolds. Manifolds don't scavenge exhaust so best to use 110 degree with manifolds.

So, an Isky E4 will work well with headers but due to very short duration it will give up before 5000rpm. I'm not familiar with the E2 that oldmics now has. The RPM300 has 112 lobe centers and should be avoided for low rpm power. We have 224 @ .050" on 110 degree that would work with manifolds. Our 270 is 224 on 108 and would work well with headers. These cams will work to 5300 or so.

Your engine should have 5750-471 heads, which flow well but are very low compression. The ECZ-G or 5752-113 mentioned earlier would raise compression.

Deck height is the distance that the piston is down the cylinder when it is as high in the cylinder as it will go. Factory spec was approx .025". Replacement pistons net approx .040". Most head gaskets are around .045. .040" + .045" = .085". To run the best you want the piston to come about .045" from the bottom of the cylinderhead. Bottom line: you need to remove material from the top of the block to get the best results.

http://ford-y-block.com 

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

Some examples I've done with a mild 312 is as follows> 224 @ .050 270 running duration was ok. That suggestion was given to me from barns & reese racing. Later I swapped it out for a 235 @ .050 270 running duration and the engine ran alot better which showed me these cars were under cammed for any real performance. But I have had some real good performing yblocks from the factory (1957 ford 300) 272? that run like a bat out a if it had wings it would fly.Don't know the cam specs it had but my guess would be the one with a running duration of 252 ????? I've also run the 232 @ .050 ma259 with great results as well. Sooooooo as you can see choosing a cam is not always easy. My pretty well stock 56 sunliner 292 yblock has a 220 @ .050 264 with a fordomatic tranny and I wish I had gone to at least a 224 @ .050 with a running duration of 270 when I changed it several years ago. Some of the other gurus on this site can break down these numbers for you and tell you what they mean such as the larger the # at .050 the hotter or more radical the cam and the more the valve is opened. Go too much and you lose your bottom end. These numbers I'm showing you here are what I call mild to mild + meaning street to mild street and strip.

-Gary Burnette-