Mild 302 build
#1
Mild 302 build
I'm building a 302 to put in my 81 cj8. I think it's going to weigh about 3300 lbs .It has 3.73s, a tremec t176 and will most likely be running 31s .I have a long block from a 96 exploder with the gt40 heads. After tearing it down I've findf that it doesn't need any machine work. Was a 40k engine that sat for a while so it's getting new rings, seals, and bearings. From the factory I think it put out 210hp/280 torque . I'm aiming for a goal of 275hp/325tq. Its my first real engine build so I don't want to aim too high. I'd really like to keep the engine appearing period correct .I have an autolite 4100 with the 1.08 primaries I'd like to use . What's the best, more truck oriented intake that would have been available in 81? Iron or aluminum doesn't really matter. How good is the factory cam for what I want? Is there any out there that would help me out with more torque? What about the factory cam with higher ratio rockers? Exhaust I think is going to be block hugger shorty headers with maybe 2.25 or 2.5" duals and an x pipe. Or maybe 2.25" or 2.5 from the headers into a y and a 2.5 or 3" single.
#2
The Explorer cam is a pretty good one as is for what you want to do. Lift with 1.6 rockers is .422/.451, change to 1.7's and it goes to .445/.473. Advertised duration is 256/266 with a 116 LSA. I've run one with a Ford A321 intake (same as the 60's Shelby Cobra dual plane highrise) and a Holley 570 Street Avenger with 1.7 rockers. This was in an 89 Ranger backed with a Toploader 4 speed and 3.73 rear. A pure pleasure to drive. Ran just like an EFI motor. Started and ran on it's own cold down to 25*F without a choke.
#3
#4
IMO. You will need a little bigger cam like a FRPP E-303 or something mild from Comp. Also the 96 gt40 heads could use some bowl work, and shave above 0.020 off the heads. I will also recommend better valve springs if upgrading the cam. As the stock springs will allow the valves to float. A decent dual plain intake will be helpful.
I built a 302 with a E-303 cam, GT-40-P heads (97 Explorer), bowls blended, 0.025 shaved off between the heads and deck, 1.6 roller rockers, Cobra Intake, 65mm throttle body, 24# injectors, 1-5/8 shorty's, no cats, 2.5 dual exhaust, 3.73, T5 trans, 14 degrees of timing on 93 octane. Now that is EFI, but it made 275hp/320tq to the tires.
I think you have a good plan, and can get to your goal with a mild cam, a little head work, mild intake, and carb. I can't honestly recommend a carb and intake. I'm more of a EFI guy.
I built a 302 with a E-303 cam, GT-40-P heads (97 Explorer), bowls blended, 0.025 shaved off between the heads and deck, 1.6 roller rockers, Cobra Intake, 65mm throttle body, 24# injectors, 1-5/8 shorty's, no cats, 2.5 dual exhaust, 3.73, T5 trans, 14 degrees of timing on 93 octane. Now that is EFI, but it made 275hp/320tq to the tires.
I think you have a good plan, and can get to your goal with a mild cam, a little head work, mild intake, and carb. I can't honestly recommend a carb and intake. I'm more of a EFI guy.
#5
Should have stated in aiming for 275/325 at the flywheel . I'd like to drive it like that for a while and see how much i really need more power . I'm thinking i really won't because it's so light. But i got my parts back from the shop . They cleaned it, checked everything, and put in new freeze plugs and cam bearings. Said no machine work was necessary . I have to figure out what I'm going to do for a fuel pump and the brackets/accessories on the front too. There's no power steering or ac. Just an alternator and water pump to run. I may find some older v belt brackets . For the distributor ithink a 85 mustang one is what i want right? Steel gear for roller cams and ds2 ignition? I think if ikeep the expo timing cover I'll need to run an electric pump.
#6
Should have stated in aiming for 275/325 at the flywheel . I'd like to drive it like that for a while and see how much i really need more power . I'm thinking i really won't because it's so light. But i got my parts back from the shop . They cleaned it, checked everything, and put in new freeze plugs and cam bearings. Said no machine work was necessary . I have to figure out what I'm going to do for a fuel pump and the brackets/accessories on the front too. There's no power steering or ac. Just an alternator and water pump to run. I may find some older v belt brackets . For the distributor ithink a 85 mustang one is what i want right? Steel gear for roller cams and ds2 ignition? I think if ikeep the expo timing cover I'll need to run an electric pump.
#7
Would i need to match the alternator bracket with the timing cover and water pump? So everything will line up properly? That expo serpentine system was ugly so i sold the brackets. Would i have to swap the harmonic balancer too? It looks like the pulley is part of it not just bolted on but i could be wrong
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#8
Never run the Exploder balancer so couldn't say. All the ones from 70-to the end for everything else had the same pulley offset. (cept the 1st gen Bronco) I used a late 80's Crown Vic timing cover (no fuel pump boss) and a late 88-91 Vic water pump (aluminum) and everything lined up to a stock 70's alternator bracket and spacer (for the pivot bolt) I later fabbed an aluminum bracket for the alternator using the steel bracket as a template. The 331 is 28oz son you'd need a late 80's 50oz balancer from another application than the 'sploder if that didn't line up.
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