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I am in the middle of rebuilding my father in laws 390 and have a question. When I had Napa do the machine work we talked about getting a RV cam that would not have a lumpy idle. Well all the parts came in and I'm a little surprised at what the specs are and am wondering what this is going to be like. The motor is going in a 65 F100 short bed with a T18 and 3.25 gears. It has a 2b 500 Holley on it and should be close to stock for compression. The over haul kit Napa supplied was based on a '68 LTD 390 which is what we started with. The cam specs are:
I am in the middle of rebuilding my father in laws 390 and have a question. When I had Napa do the machine work we talked about getting a RV cam that would not have a lumpy idle. Well all the parts came in and I'm a little surprised at what the specs are and am wondering what this is going to be like. The motor is going in a 65 F100 short bed with a T18 and 3.25 gears. It has a 2b 500 Holley on it and should be close to stock for compression. The over haul kit Napa supplied was based on a '68 LTD 390 which is what we started with. The cam specs are:
What pistons are you using? Check the compression height and piston type. In '68 a slightly dished piston with valve reliefs and a compression height of 1.76 was good for a 9.5:1 CR according to Ford. Same thing with flat tops was 10.5:1. TRUCK 390s used 410 pistons with a compression height of 1.67--that gives very low compression.
I'm not too worried about the cr I know it's not going to be crazy. I'm more worried about the sound. Myself I would probably like it but he won't if it makes him think there might be something wrong with it.
Yep, that's an RV cam. It's not going to be lopey. The "advertised" duration specs are somewhat misleading. It's the @.050 specs that count. Good cam for what you're doing. I used one identical to that in a stock 400M with the same combo (Holley 500 2 bbl and longtube headers). Really woke up that 400. You need headers on your paw-in-law's 390 to fully realize the potential of the 390. They'll improve the fuel mileage too. The flat log manifolds are the single worst feature of these engines. They've got excellant heads, but for some reason Ford chose to "put a cork on em" with those manifolds.
I'm not too worried about the cr I know it's not going to be crazy. I'm more worried about the sound. Myself I would probably like it but he won't if it makes him think there might be something wrong with it.
8 or 8.5 compression will be a pooch maker. 10.5 compression will ping. I'd at least check it.....
Those specs look very familiar, like maybe a copy of the old Ford cam that was sold as a mild upgrade over the 390GT/428CJ cam. Back when you could still get a new one from Ford (around '80), I put one in a new 390 I built for a buddy's '74 F100 4x4, and it ran real good with flat tops, headers, Streetmaster and an 1850 600cfm Holley
Yea not sure where the grind I got originated from but we are going to try it. The guy I have helping me with my measurements looked my stuff over tonight and was ok with the cam specs. I guess we'll see.
Several companies offer that same grind. Summit, Melling, Sealed Power, probly lots more that just these. Worked great in an 8 to 1 400, definately not a snoozer.
I was wondering since compression ratio was mentioned if anyone had an idea what the pistons I was supplied with will make it. I can get the numbers off the heads if needed.
I was wondering since compression ratio was mentioned if anyone had an idea what the pistons I was supplied with will make it. I can get the numbers off the heads if needed.
Your link tells the tale. Those are pickup pistons. Look on the label it says "390/410". Those will sit down the hole in your 390, affecting power and efficiency. You will still have a good motor with your cam, but those pistons will cost you power and some mpg.
I noticed the pistons are just a little shorter after joining a new and old piston together with a wrist pin. I wasn't really sure what they will do since the relief area on the new ones is a a lot smaller and it is domed up. The originals while taller had a larger relief that was flat. I just don't want this thing to run like a 360.
Hmm I'm not sure what I want to do. I did call Napa and see if they can swap them. I don't want it to be a dog but don't want it to have to run on premium either.
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