Thread: first 390 build

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Hi I'm riley I'm new and I'm just needing some expert advice on my 390 build so thanks for your time and here's what I got

390 bored .30
650cfm carb
4 hole spacer
Probe pistons 1.765 4cc
D2teaa heads milled 65cc 2.09/1.66
275deh cam @.50 213/232. 275/285 514/541 110lsa
.020 gasket
Stroke 3.78
Rod length 6.486
Deck clearence .029
11:19.1 compression
Full length big tube headers
2.5 duel exhaust flowmaster 40s
C6 stock stall
3.25 gears

Hi Riley.. Nice to see you here! A couple of questions for you.
1. whats the motor going in?
2. what's the purpose - what's your goal?

I'm not certain the heads (1972 truck heads I believe) are going to be helpful if you want to make big rpm. And I don't believe they have hardened seats.
But if you just want to make torque at lower rpm, then maybe they fit your plan...

My goal is just to have a fun street truck from 2500-5800 rpm and i had the heads rebuilt with the 2.09/1.66 valves hardened seats and keepers and been milled to 65 chamber, and its goin in a swb 1968 f100

Thanks for the greeting and so forth i didn't want to big of a cam so the machinist at Henson racing engines recommended be the 275 dual energy, said it will have the good sounding idle and is the biggest cam I can go with stock converter

Welcome to CHR. The thing that jumps out at me is that 11.19:1 compression ratio, which is sky high for iron heads with pump gas that we have today.

Well I want to run 110 octane race fuel, its only gonna be a weekend driver
Plus I might take it to the strip once in a blue moon

Ya I looked at the h-278-2 cam and the comp cam 280h but the 280h seemed to big for stock converter with 3.25s and I asked my machinist at Henson and he replied that I would be happier with the duel energy cam due to something about Fe heads not breathing well on exhaust side, but the h-278-2 cam seemed interesting

Could you send me a link?

I found the specs well its (to) big, its advertised as 3000-6200 I think that's to much for what I want honestly I don't think my gears nor a stock stall would work sorry if I didn't specify I don't plan on going above 3.25 rear or a stock stall but hey its my first build, I'm running a 2600$ budget

I thought and looked around I think ill go with the cam that Henson had recommended me, I know I'm prolly leaving some power on the table but I'm ok with it as I feel a more mild cam will leave me with more power in my operating range with the taller gears and stock stall, but just outta curiosity what kina numbers do yall think I will be making with this setup I already have??? And thanks for y'all's input, if I decide to change my mind I think I will just end up goin to the h-278-2 cam

Ya I'm having issues to it posted my comment before yours popped up and I really like the looks of the 296 I don't honestly know if I could use it with a stock stall or not, but if I can manage more money I will definitely go with the 296,
So what would the power difference be between the 296 and the 275deh With the setup I got?

Whatever cam you get-you should look at getting lifters that have an edm micro hole to oil the cam lobe and use combo with hollow push rods to oil the top end rockers.

Are the 390s oiling system that bad!? I heard they weren't good but didn't think they were oil starved

Originally Posted by DennyW

The cam you have picked is rated at 353.8hp---430.2 torque

Is that with the 275 or 296? And how do you get power numbers? I apologize Im still a rookie that's why I had Henson racing do alot of my engine planning for me

Ok, I'm looking for a good loud choppy to rough idle quality, around the general 400hp and tq range, strong midrange to top end, stock stall and 3.25 gears, with a 2600$ budget
And what I'm working with is a 390 block bored .30 stock stroke 3.78 6.486 rod length and the heads I had worked over, with a high compression to run race fuel