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Discussion Starter #1
Hello, So I have a stock pre 86' sbc 350 in my 1975 F150 I picked up a few weeks ago. It's got a bent valve and a wicked exhaust leak. So I was going to put new heads and headers on the motor, and figured while I was at it that I might as well put a new cam in. I'm pretty stuck on the heads I want to get (unless someone provides a good reason I shouldn't get them/ should get others). I just don't know how to properly pair a cam up with heads.
The heads I'm looking at are ProMaxx Performance Freedom 2122 (https://www.summitracing.com/parts/pmx-2122/overview/make/chevrolet).
Any insights as to what cam I should put in would be awesome. Maybe an article to read about how to do this myself in the future? Always willing to learn. :thumbup:
 

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Hello, So I have a stock pre 86' sbc 350 in my 1975 F150 I picked up a few weeks ago. It's got a bent valve and a wicked exhaust leak. So I was going to put new heads and headers on the motor, and figured while I was at it that I might as well put a new cam in. I'm pretty stuck on the heads I want to get (unless someone provides a good reason I shouldn't get them/ should get others). I just don't know how to properly pair a cam up with heads.
The heads I'm looking at are ProMaxx Performance Freedom 2122 (https://www.summitracing.com/parts/pmx-2122/overview/make/chevrolet).
Any insights as to what cam I should put in would be awesome. Maybe an article to read about how to do this myself in the future? Always willing to learn. :thumbup:
That's a large 72 cc chamber head with huge 225cc ports, on a stock bottom end 350 they will be a dud with insufficient compression and zippo port velocity. I'm assuming you're thinking big cam which will make bad matters worse. You need to rethink this unless you can come up with a good reason to put very high performance heads really intended for a 383, 400, 406 or bigger SBC as these will be totally DOA on a 350 without a ton of compression and a well built bottom end.

Bogie
 

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The intentions for this truck is to just have a street truck, no drag stips. But it would be nice to have some good power.
I think I picked those out as heads to use to later go to a 383. But maybe I should get some different heads and a cam to go with the stock 350, then later upgrade everything to 383 parts at the same time?
What's your guy's recommendations here?
 

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The intentions for this truck is to just have a street truck, no drag stips. But it would be nice to have some good power.
I think I picked those out as heads to use to later go to a 383. But maybe I should get some different heads and a cam to go with the stock 350, then later upgrade everything to 383 parts at the same time?
What's your guy's recommendations here?
Unless that 383 build is going to show up in just a couple of months, the 350 needs to have 185-190cc intake ports. Get 64cc chambers, as this will help raise your stock dismal 8.2:1 compression up to 9.7:1 or so. Also get straight plugs, angle plugs interfere with nearly all street and budget headers, clearing only full-on big tube.race headers usually.

https://www.summitracing.com/parts/pmx-2169/overview/
https://www.summitracing.com/parts/pmx-2181/overview/

You can either sell, or port/have porting done on one of these bigger down the road for the 383.

You going to switch to a retro-fit hydraulic roller cam, or roll the dice and take a chance on getting a new flat tappet cam and lifters through the break-in process successfully??
 

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Discussion Starter #6
You going to switch to a retro-fit hydraulic roller cam, or roll the dice and take a chance on getting a new flat tappet cam and lifters through the break-in process successfully??
Maybe I've been reading misleading stuff, because everything that I was reading made it seem like it has hydraulic lifters already. Which would be the preferred method, I'll do some more reading to see how difficult/how much work needs to be done to do that. I don't have the biggest assortment of tools or space at my apartment. :pain:
 

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Maybe I've been reading misleading stuff, because everything that I was reading made it seem like it has hydraulic lifters already. Which would be the preferred method, I'll do some more reading to see how difficult/how much work needs to be done to do that. I don't have the biggest assortment of tools or space at my apartment. :pain:
Pre-86 engines are strictly hydraulic flat tappet, hydraulic rollers only started in 86-newer engines.

Hydraulic flat tappet is a real crapshoot nowadays, as the OEM's no longer use them quality has gone to crap, and motor oils no longer have the sliding wear/high pressure additives these cams need, meaning you would need the special break-in and race oils.

Do some searching on flat tappet cam failure, and flat tappet cam oiling.

How in the heck did you manage to buy a 1975 F-150 with a Chevy engine transplant?? I would have run for the hills as soon as they opened the hood.
 

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Pre-86 engines are strictly hydraulic flat tappet, hydraulic rollers only started in 86-newer engines.

Hydraulic flat tappet is a real crapshoot nowadays, as the OEM's no longer use them quality has gone to crap, and motor oils no longer have the sliding wear/high pressure additives these cams need, meaning you would need the special break-in and race oils.

Do some searching on flat tappet cam failure, and flat tappet cam oiling.

How in the heck did you manage to buy a 1975 F-150 with a Chevy engine transplant?? I would have run for the hills as soon as they opened the hood.
The reasons I bought the truck despite the chevy transplant was because the body is straight, with 2 small rust spots on the corners where the cab meets the bed. Small rust hole which has already been neutralized, and I plan on getting a replacement patch panel and weld it in anyways. The underside of the truck is in great shape, and so is the bed and interior (just a single rip on a seam on the bench seat).
The wiring in the truck was a bit wack which is why I'm currently in the process of ripping it all out and replacing it, and I knew it had a bent valve when I bought it which is why I'm looking at new heads for the thing. And I would rather have a sbc 350 than the Ford 460.

Overall I got the truck for $840 and it was fully intended to be a project truck.
 

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The reasons I bought the truck despite the chevy transplant was because the body is straight, with 2 small rust spots on the corners where the cab meets the bed. Small rust hole which has already been neutralized, and I plan on getting a replacement patch panel and weld it in anyways. The underside of the truck is in great shape, and so is the bed and interior (just a single rip on a seam on the bench seat).
The wiring in the truck was a bit wack which is why I'm currently in the process of ripping it all out and replacing it, and I knew it had a bent valve when I bought it which is why I'm looking at new heads for the thing. And I would rather have a sbc 350 than the Ford 460.

Overall I got the truck for $840 and it was fully intended to be a project truck.
OK, it makes sense for the good body.....but the 460 Ford is one hell of a stout engine. with just a couple of simple mods it really wakes up, and can be stroker'd far bigger than any stock Big Block Chevy can, the Ford will go clear to 557" in a stock block. :thumbup:

And I'm a Chevy guy, so you know that's saying somethin'...
 

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OK, it makes sense for the good body.....but the 460 Ford is one hell of a stout engine. with just a couple of simple mods it really wakes up, and can be stroker'd far bigger than any stock Big Block Chevy can, the Ford will go clear to 557" in a stock block. :thumbup:

And I'm a Chevy guy, so you know that's saying somethin'...
I have much to learn it looks like. Looking at some of the 600hp builds for a 557 show they cost about the same as a 383 stroker would...
 
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