460 stock short block revisions/questions - 460 Ford Forum
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post #1 of 7 (permalink) Old 07-05-2014, 08:41 PM Thread Starter
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460 stock short block revisions/questions

Okay, after my first thread, I have done the following (based on what I have either learned from reading countless posts, or asking questions to forum members offline).

4700# ish pound 76 Mercury 2 door Grand Marquis.

C6 with 2400 stall

3.50 Traction-Loc rear

I have purchased the following:

Comp Cams XE262h cam, valve springs, and lifters.
Holley 750 DP set up and built by a local racer with years of hi-performance Holley builds.
Scotty the Mad Porter's Distributor
Stan's 1-7/8" long tube headers
Holley 135gph mechanical fuel pump
RPM Air Gap intake
1" spacer
Cloyes true roller 1968-1971 "straight up" timing set

Not that it really matters, but new water pump, new oil pump, Felpro Gaskets, high Zinc oil to break in cam, synthetic oil for afterward, etc.

My question(s) are as follows:

I had intended to have my builder build (read modify) my stock short block with the stock internals, the new 262 cam, new lifters, new springs, etc and do a mild port on my D3 heads as per Scotty's instructions.

My builder looked at my pile of parts, and said, "Why don't you go with the Edelbrock RPM heads and a XE274h cam?"

My question is this, after a lot of reading here, it appears I may have issues with valve clearance if I do. An old thread that was never really "finished: entitled "Comp Cams Xtreme Energy" a guy asked the same type question and was handed a reasonable pile of responses ranging from "Should work" to "wont work".

Has anyone done it? Can I do it without issues? I don't want to buy the 272 cam, stick it in, have him clay the pistons, and say, "Well, I wish ......"

Id it'll work, I'll return the XE262h and buy the Edelbrock heads, and XE272h cam. If it wont, I'll stick with the D3 heads, mild port, etc.

This motor will be used for about 3-4 months at which time I am building a stroker to replace the "Stock" 460.

The car will se street and strip use, and I want to keep RPM down at maximum of 6k for longlevity.

I'm trying to have these mods made by next weekend for a car show for what it's worth, so if there's going to be head/valvetrain changes, I'm going to need to expedite the parts tomorrow.

Thanks in advance.

Scot Hildreth
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post #2 of 7 (permalink) Old 07-05-2014, 10:21 PM
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I don't understand why someone would take an engine with about 7.8 to 1 compression ratio and start putting larger camshafts in it. Change out the pistons and at least get the compression up to 9 to 1 ratio so you can realize some benifit from a larger cam. Other than that, a great project.

Oh yea, why are not you getting a custom cam from one of the vendors here that will fit your application spot on?

Last edited by DanE; 07-05-2014 at 10:42 PM. Reason: finish statement
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post #3 of 7 (permalink) Old 07-06-2014, 08:38 AM Thread Starter
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DanE,

Currently neither you nor I are certain what those pistons sit below the deck, therefore we can't be certain regarding the compression ratio of the set-up as it sits.

There are multiple posts regarding the use of the Xe262h grind (or similar) cam in the stock short block with porting, headers, intake, carb, etc. with satisfactory results.

I have talked to Scotty extensively, and he is going to have someone grind a cam for my stroker. Given the time constraints, I wasn't going to have a custom cam ground at this time for a motor I was going to flog for 3 months.

If I used the Edelbrock heads, I would use the 75cc version, yielding me another 1.5 or so points on my CR.

I had no intent on determining the pistons are .060 below deck, running to find the thickest head gasket I could find, and grabbing a mother thumper cam to only complain about problems later.

My question was regarding the use of the 274 cam with the Eddy heads - primarily valve clearance.

Thanks again.

Scott
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post #4 of 7 (permalink) Old 07-06-2014, 10:14 AM
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Scott, I can't imagine that you would have any piston to valve clearance issues.

The Eddy heads have the same valve location as the stock heads. "The Mad Porter" ported a set of C9 stock heads for me (331/199 CFM at .600") and with the pistons .004" in the hole and .030" Cometic head gaskets, I had over .200" valve to piston clearance on one of "The Mad Porters" cams with .620" lift.

When you post on here and a member sees something that he thinks is off, you may get a commet on that issue. Like---- Are you going to use the Air Gap manifold on your strocker build? If not, it is too much manifold for your present build.

At any rate, best to you and yours.

Last edited by DanE; 07-06-2014 at 11:28 AM. Reason: added content
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post #5 of 7 (permalink) Old 07-06-2014, 11:28 AM
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Edit; Quench is important with these motors. If yours is a "stock" short block, I would guess that yours pistons are about .030" in the hole. It seems that the preferred quench is around .040". And seeing as how the average head gasket used is around .040", you can see why it is recommended to "0" deck your block deck. Because I am running a lot of compression (10.8 to 1 ratio) with cast iron heads, I cut my quench down to .034" and had "The Mad Porter" cut "singh groves" in my heads. He has the preparation of these heads on his facebook page under the title "Project Black Bird" which refers to my 1973 Thunderbird, which is getting a dual quad, dual plane 502" engine built for mid-range torque.

Dan

On a heavy street vehicle, it is better to undercam than over cam, especially is the compression is on the low side.

Last edited by DanE; 07-06-2014 at 11:34 AM. Reason: added content
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post #6 of 7 (permalink) Old 07-06-2014, 12:36 PM
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Quote:
Originally Posted by DanE View Post
Edit; Quench is important with these motors. If yours is a "stock" short block, I would guess that yours pistons are about .030" in the hole. It seems that the preferred quench is around .040". And seeing as how the average head gasket used is around .040", you can see why it is recommended to "0" deck your block deck. Because I am running a lot of compression (10.8 to 1 ratio) with cast iron heads, I cut my quench down to .034" and had "The Mad Porter" cut "singh groves" in my heads. He has the preparation of these heads on his facebook page under the title "Project Black Bird" which refers to my 1973 Thunderbird, which is getting a dual quad, dual plane 502" engine built for mid-range torque.

Dan

On a heavy street vehicle, it is better to undercam than over cam, especially is the compression is on the low side.
Normally builder pistons end up right around .020" or so in the hole.....and that's not taking into consideration the deck surfaces being out of square, as most are. Quench should never be more than .060". Lower compression engines will be detonation prone with too much quench distance even with the lower cylinder pressure. I've run as little as .020" piston to head with steel rods and got away with it. Most of the big builders on here will tell you that that's too close, but it worked.

Remember that bigger cams with more than stock overlap will bleed off cylinder pressure at lower RPM's. That's why static compression is always higher than dynamic compression.
Rob

Rob Hawes-Anchorage Rod Works-Anchorage, Alaska

Last edited by White Lightning; 07-06-2014 at 12:38 PM.
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post #7 of 7 (permalink) Old 07-12-2014, 01:42 PM Thread Starter
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Well, for what it's worth...

The pistons were only .011 below the deck. So, with a .027 (compressed) gasket thickness of the cometic head gasket, and the D3 heads combustion chamber, the compression of the interim motor will be a whopping 8.57 to 1.

Not awful, considering how it could have been.

Not bad quench either.

It should at least be entertaining until the stroker is complete, considering the two stinking days of port work done to the heads.

As soon as the motor is in it, and everything is tuned, I'll add a video of the car/engine. Maybe I'll take it to the track for some before/after time slips (old 460 v. stroker).

Thanks for all fo the help from Scott The Mad Porter and Stan at Powertrain.
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