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Mar 7, 2010 | 12:03 PM

F-250 restorer

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From: Near Los Angeles

HP project

When I started my 390 to hp 300 swap I was a novice mechanic, with very little hp experience. While educating myself about the project, I realize I have made some mistakes during the build, and wanted to throw it out there to you guys for a bit of guidance.

What I thought I had paid $300 for was not a porting job, but rather simply port matching to the gasket. I did have the 1.94 sbc and 1.60 valves installed, and that has made a difference. But with the 500 Edelbrock and auto trans, I am looking at ways of getting a bit more power out of it.

Since I will soon be replacing my old 390 radiator with an aluminum cross flow, and dual puller fan set up, and have to pull the cam at that time to allow me to change the clunking timing gears, I am considering going to a larger cam. The cam needs to come out because I had it ground to my specs, and the base circle is smaller than oe, and making the lifters clatter like crazy. And the new gears knock. Great, ah?

I think I could either pull the head and fully P&P the head, unshroul the intake, polish the chamber, and stay with the existing cam. Or, install a slightly larger cam, and dial in the carb.

Any feed back is appreciated.

Mar 7, 2010 | 12:24 PM

Harte3

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From: Spokane, WA

Whoops! A gasket match is usually not recommended...a port match is mainly to remove the ledges sticking out in the down stream flow. De-shrouding the valves, polishing the combustion chamber and exhaust runners, removing the AIR bumps (if any), etc., are part of the usual port/polish job.

Mar 7, 2010 | 06:12 PM

dustybumpers

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From: In my own world

Quote:

Originally Posted by Harte3

yup, sand mold lines, etc. you are already talking of the 1.7 rockers, which will give your cam a larger profile. put the same came, or same version of it you had before, and I think you will be happy. remember that the motor you are building will never be a high horse power engine, but will be a brute for torque.

Mar 8, 2010 | 07:03 AM

chrlsful

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From: Lawrence Swamp

will be a brute for torque

I think that is what many on this forum (300 I6) R looking for. The only thing I know right now to focus on a tq bump up is long tube headers. Doing a real short and simple listing what else would be modified to focus on low rev tq improvements?
This non-mechanic gives thanks to the (used respectfully) Gearhead Gods.

Mar 8, 2010 | 07:55 PM

dustybumpers

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I just got a chuckel earlier, a diehard chevrolet fan at work is haveing trouble with his pickup. I told him torqueconverter.he took it to trans shop, and haha it needs a new converter. when he ask the mechanic what to do about pulling his trailer with the truck, he was told buy a ford with a 300. he just called me, and bought a ford.

Mar 8, 2010 | 09:14 PM

F-250 restorer

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From: Near Los Angeles

That's pretty good, Dusty!

I'm not really sure what I'm going to do with my engine. I have to swap the timing gears, and was thinking about using the 256 isky cam from the first engine since it mic's at oe. Still it frightens me. Isky is real close here, so I may pick up their 262 duration cam and put that in. It actually has slightly less lift than the 256. If I do that I don't think I'll change the lifter ratio.

What do you think?