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cam choices at rebuild

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82f150racetruck
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cam choices at rebuild

Post #1 by 82f150racetruck » Fri Feb 21, 2014 7:27 pm

I have a 1982 F150 4x4 and am getting ready to have the 300 six rebuilt. It runs on propane. I have headers and dual exhaust and will probably be putting on a 4 barrel intake and carb. in the future. I was wondering which camshaft I should use to get a little more preformance out of it but I dont want to sacrifice a lot of the low end torque. any help would be greatly appreciated. Also I should mention I live in Colorado Springs Colorado, at high altitude where the air is thin. Thank you.

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80broncoman
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Re: cam choices at rebuild

Post #2 by 80broncoman » Sat Feb 22, 2014 9:27 am

It is going to be dual fuel or LPG ONLY
And Is it still going to used as a working truck (hauling/Towing over 700lbs)?

first
being at a higher altitude I'd raise compression no matter what.

If LPG ONLY I'd raise is even more.

Have to know usage, compression to pick a cam.
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Real men don't wear Bowties
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80 bronco FUV (farm utility vehicle)300 T-18 3.50s EFI head, offy C dual plenum, 500 edel carb, 1.7 roller rockers, Crane 260 cam EFI Exh

82f150racetruck
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Re: cam choices at rebuild

Post #3 by 82f150racetruck » Sun Feb 23, 2014 9:52 pm

It is going to be LPG only. It is my daily driver, back and forth to work. A one way trip to work is about 5 miles of city driving and about 15 miles of highway driving. As far as compression goes I was told that LPG doesnt like higher compression, so I was going to go with stock compression and I think 30 over pistons. But if you have any sugestions please let me know as I dont really know that much about running on LPG. And I am not finding much about it to help me decide what to do.

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80broncoman
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Re: cam choices at rebuild

Post #4 by 80broncoman » Wed Feb 26, 2014 8:21 am

Propane has something like 110 octane, IF I remember correctly. Being in Colorado Springs you are up at about 7-8K feet right?
I sure you are aware that the gas they sell at higher altitudes is usually lower octane compared to what we get at lower heights.

I go to about 10.5 and wouldn't be worried if it even came in around 11 to 1.
OAPSE Union Member

Real men don't wear Bowties
When it come to engines If its .001 loose nobody knows, But if its .001 too tight EVERYBODY KNOWS!!
80 bronco FUV (farm utility vehicle)300 T-18 3.50s EFI head, offy C dual plenum, 500 edel carb, 1.7 roller rockers, Crane 260 cam EFI Exh

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Re: cam choices at rebuild

Post #5 by BIG 6 farmer » Thu Feb 27, 2014 12:42 pm

LPG? Yes on the higher compression. A shorter duration camshaft, with faster ramp rates. Will raise your lower RPM cyl. pressures. Something like an Isky Mile-a-more would be my pick, or something close to that. :hmmm: You will have better power from idle to 3500? RPMs The sweet spot for a Truck Engine. :thumbup:
83 F 150 SB 4x4 300 six NP 4speed - - 1950 IHC L162 (1&1/2 ton?) - 87 & 88 T-Bird Turbo Coupes - 2000 Triumph Tiger , 76 Honda GL 1000 , & other toys and parts (& junk) -

82f150racetruck
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Re: cam choices at rebuild

Post #6 by 82f150racetruck » Fri Feb 28, 2014 10:29 am

It looks like we are going to use 60 over pistons and will be milling the head to get higher compression ratio. I am still undecided on the cam but the shorter duration and steeper ramps to keep the power at lower rpm does make since. I am really going to have to research cam profiles to try and find one that is going to fit my needs. I do like the steeper ramps and shorter duration suggestion but iI would like to rev a little higher than 3500 rpms, maybe 4000 to 4500. Thanks everyone for your input and keep the suggestions coming, you never know what I might end up with , with enough great minds helping out!

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80broncoman
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Re: cam choices at rebuild

Post #7 by 80broncoman » Fri Feb 28, 2014 8:20 pm

82f150racetruck wrote:It looks like we are going to use 60 over pistons and will be milling the head to get higher compression ratio. I am still undecided on the cam but the shorter duration and steeper ramps to keep the power at lower rpm does make since. I am really going to have to research cam profiles to try and find one that is going to fit my needs. I do like the steeper ramps and shorter duration suggestion but iI would like to rev a little higher than 3500 rpms, maybe 4000 to 4500. Thanks everyone for your input and keep the suggestions coming, you never know what I might end up with , with enough great minds helping out!


Do you REALLY need to bore the block to 60 over? If the block is that bad I'd bet you could find one better. To me It just makes the cylinder walls thinner and not much else.

If you really did want to turn it to 4500 RPMa Crane 260 cam is a good choice.
http://www.cranecams.com/product/cart.p ... il&p=24078
OAPSE Union Member

Real men don't wear Bowties
When it come to engines If its .001 loose nobody knows, But if its .001 too tight EVERYBODY KNOWS!!
80 bronco FUV (farm utility vehicle)300 T-18 3.50s EFI head, offy C dual plenum, 500 edel carb, 1.7 roller rockers, Crane 260 cam EFI Exh

82f150racetruck
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Re: cam choices at rebuild

Post #8 by 82f150racetruck » Sat Mar 08, 2014 4:18 am

Can anyone tell me if you can change the rockers from the stock 1.62 to 1 to the 1.73 to 1? What modifications do you have to do if this is possible?

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80broncoman
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Re: cam choices at rebuild

Post #9 by 80broncoman » Sat Mar 08, 2014 8:59 am

82f150racetruck wrote:Can anyone tell me if you can change the rockers from the stock 1.62 to 1 to the 1.73 to 1? What modifications do you have to do if this is possible?


It depends on what type of rockers your 300 as to how you go about swapping it over.
straight stud mount rockers are by far the simplest to switch over.
You just buy what ever rockers you want and get them for a 250 Chev six (they are supposed to be 1.75 to 1 ratio)
I run a BBC roller rocker same as the 250 bowtie except is has 1.7 and 7/16 stud hole. (easy to find good used ones)
Note mine uses SBC length valves.

Now remember with the extra strain a bigger lift cam or rockers doing a rebuilt Make sure and use a All metal timing gear set.
OAPSE Union Member

Real men don't wear Bowties
When it come to engines If its .001 loose nobody knows, But if its .001 too tight EVERYBODY KNOWS!!
80 bronco FUV (farm utility vehicle)300 T-18 3.50s EFI head, offy C dual plenum, 500 edel carb, 1.7 roller rockers, Crane 260 cam EFI Exh

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