07-08-2022, 10:01 PM | #1 |
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cam question
Hello all; A friend of mine is building a fiberglass Cobra kit car. He has 373 rear gears, will use a 5 speed manual transmission, and a 302 ford engine with a four barrel carburetor and distributor ignition. He's looking for a cam recommendation to get a little more performance from the 302. Maybe a 3/4 hydraulic. Thanks in advance for any suggestions, Craig.
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07-09-2022, 12:03 AM | #2 |
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Re: cam question
Back in the mid 70's I used a Sig Erson hi-flo 1 cam with good results, but I don't know if they are even in business anymore. sorry I can't help more. haven't played with a small block ford for a long time
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07-09-2022, 01:17 AM | #3 | |
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Re: cam question
Quote:
IMO, the easiest way out of this is to speak with a minimum of three cam manufacturers TECH LINE as to the best solution. They will need to know how the car will be used, engine specs, trans type, rear, wheel size and tire diameter. IMO - You will want a roller unless it will be full competition.
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07-09-2022, 08:23 AM | #4 |
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Re: cam question
Cams start out in the stock range which gives good horse power AND torque range. As the performance level changes, there is a trade off between horse power and low end torque. The more lift the more horse power but the torque curve changes a lot so it boils down to how a person wants it to perform. For all out high speed a person goes toward high lift & high duration. For street use with the crap gas we have in this day and age then a person should go with a cam that gives best overall performance on the street between low end torque and top end speed. Most cam manufacturers explain their cams fairly well as to what the different grinds will do for the end user. If they don't, then look for another source.
I've never figured why folks still use the 3/4 lift term. 3/4 of what is the question. It's a lot more scientific now days so those old 40s terms don't really fit. This link may help some. https://www.diyford.com/small-block-...ing-camshafts/ Performance cams also require spring pressure changes and selection of different lifters depending on application. There is a lot to learn when stepping up the performance levels. Last edited by rotorwrench; 07-09-2022 at 08:37 AM. |
07-09-2022, 08:38 AM | #5 | |
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Re: cam question
Quote:
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07-09-2022, 09:15 AM | #6 |
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Re: cam question
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07-09-2022, 10:51 AM | #7 |
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Re: cam question
It's cam duration, not lift, that's primarily responsible for moving torque and horsepower up the rpm range. When discussing big/small cams, it's a reference to duration, not lift. If the replacement cam has significantly more lift, make sure that the valve springs are compatible.
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07-09-2022, 07:57 PM | #8 |
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Re: cam question
And valve to piston interference. Makes a lot of noise (briefly) if they hit. I don’t have any experience with modern sbf’s, but the keeper to valve guides can also be a problem with higher lifts.
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07-09-2022, 11:57 PM | #9 |
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Re: cam question
Good point, Miker. He should be ok with valve lift below .500, but he needs to verify.
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07-10-2022, 06:09 AM | #10 |
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Re: cam question
I've read many posts on numerous sites where "younger" guys question the term 3/4 cam. Like it's been mentioned it was just a term we used to describe a cam back then. To me it's no dumber than installing a RV cam a name used today. What, your gonna install a RV cam then take it camping.
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07-10-2022, 08:29 AM | #11 |
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Re: cam question
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07-10-2022, 08:55 AM | #12 |
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Re: cam question
Yeah, 3/4 was describing between stock and full race. I remember ... ... when RV cams came out. It was when gasoline was de-rated (lead) and they were used mainly to allow increased performance (CR) on cheap gas. As mentioned, RV to me refers to a LT engine. BTW- How is the '56 coming along?
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07-10-2022, 12:01 PM | #13 |
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Re: cam question
The one cam manufacturer that always makes me scratch my head is Comp Cams. They start out as HV series then they go to classic thumpr. From there they go to mutha thumpr and then on to the big mutha thumpr. If all a person cares about is how much their engine thumps then they can buy a Comp Cam product.
If a person want to really know what a particular cam grind will do for you then a person needs to look at the product catalogs for the different manufacturers. Their descriptions mention compression ratios usable with and carburetor CFM recommendations and the like. There are a lot of listings for the Ford 302 in Isky and Crane listings. A person has to settle on which series of 302 to use as well. They changed to roller engines in the later years and that makes a difference. Later ones were set up for fuel injection. Older engines were carbureted but some have smog dog heads. What type of carburetor or fuel injection to use, what type of exhaust to use, how much compression to run and what type of fuel do you want to buy for this project car. If money is no object then a person can have an engine built for them per the builders recommendations. My own conclusions would be to do the research and checking on line and then make an informed decision where to go from there. A lot of forums deal with Ford cars, trucks, 4X4s, and all will give a different recommendation about what to use. I'll pretty much guarantee that you won't find a listing that states"good 3/4 race cam for 302". |
07-10-2022, 03:40 PM | #14 |
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Re: cam question
https://customfordcams.com/products Not making a recommendation but seems to have a list of questions covering the things.
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07-10-2022, 06:13 PM | #15 | |
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Re: cam question
Quote:
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07-12-2022, 02:42 PM | #16 |
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Re: cam question
He’s sure asking the right questions and making the right remarks. If he’s got the data base and engineering knowledge to support it he’d be a great resource.
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