Mild 302 build

Reply Subscribe

Thread Tools

Search this Thread

Oct 31, 2018 | 02:38 PM

craveman85

Thread Starter

Mountain Pass

Joined: Oct 2012

Posts: 124

Likes: 0

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.

Oct 31, 2018 | 09:20 PM

baddad457

Hotshot

Joined: May 2003

Posts: 11,141

Likes: 25

From: south louisiana

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.

Oct 31, 2018 | 10:24 PM

mark a.

Lead Driver

Joined: Mar 2004

Posts: 8,924

Likes: 153

2 things that should always be checked with mics and a bore gauge reading in .0001" main bearing bores and all the rods bores. If a main or rod bore is out anymore than .0002" now is the time to get it fixed.

Nov 2, 2018 | 07:28 PM

Screwed 05

Junior User

Joined: Aug 2017

Posts: 60

Likes: 0

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.

Dec 7, 2018 | 04:33 AM

craveman85

Thread Starter

Mountain Pass

Joined: Oct 2012

Posts: 124

Likes: 0

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.

Dec 7, 2018 | 07:21 AM

baddad457

Hotshot

Joined: May 2003

Posts: 11,141

Likes: 25

From: south louisiana

Quote:

Originally Posted by craveman85

Carbed ? I've run the low pressure 30-35 gal/hr electrics on both my 77 Comet and an 89 V8 Ranger for 20 years now. Plenty of flow for a carbed motor. Only time this runs short on my 3x2 carbed 331 is when the filter needs changing. And that's at WOT. The distributor you'll need is the 85 Stang with manual transmission. The automatics that year had a flat tappet cam. I fabbed an aluminum alternator bracket for my 331, it's just got the alternator and water pump setup with ebay bought aluminum pulleys. As for intake and carb, I would run any of the high rise dual planes, Edelbrock's RPM or older F4B, Ford's C9OX, their newer Ford Racing A321 or the old Shelby Cobra intake. Wieand Stealth is also a good one. All perform from idle to 6500 despite what they advertise. Carb ? Holley 600-650 vacuum secondary..

Dec 7, 2018 | 07:51 AM

craveman85

Thread Starter

Mountain Pass

Joined: Oct 2012

Posts: 124

Likes: 0

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