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May 29, 2001 | 03:27 PM

traildawg

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Senior User

Joined: Jul 2000

Posts: 429

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From: Lima, OH

Heads

I'm getting ready to go scavenging through the salvage yards to find another head for my 4.9L, but wanted to know if there's any differences through the years I should look for (or avoid). This head will be going straight to the machine shop for massage work, with performance being the key factor. Will any 300 head work on my FI engine, or do I have to stick with a FI head? Also, what's the story on the 240 head? Seems like I'm always seeing alot of talk on here about them....what's their benefit?

TrailDawg
https://www.ford-trucks.com/dcforum/User_files/3aaa4bac6f539876.jpg
1993 F150 2WD
6" Pro-Comp Stage II Lift w/35's
Auburn Pro-Series Diff. w/4.30 gears
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May 29, 2001 | 05:25 PM

Eddie

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Joined: Nov 1999

Posts: 780

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Heads

The 240s as used in passenger cars in the Sixties had small "bathtub" combustion chambers, and therefore higher compression. In 1971 and '72, Ford dropped the heck out of CRs across the line, 240 included. I don't remember the cc measurements offhand, but I know that the '72 gets you a streetable 9 or 9.5; the earlier head puts you up in the 10-1 range.

Combine that w/Chevy 1.9/1.6 valves and port and bowl work--now you've got something!

Just speculating, but I would imagine that since 300's were used in trucks only, their compression was lower to start with.

I personally am going to stay with an emissions head, '87 or later, because I like the current-tech, high-swirl, heart-shaped chamber shape, though I'm going to have to do quite a bit of extra work to eliminate that godawful boss for the air injector in the roof of the exhaust port, and relocate the air injectors to the header.

Getting seriously into that head is my next project--and my only compression concern is in keeping it low enough as I'm going to build a ground-up blower motor,

Eddie