The Better 331?
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Elder User
Joined: Feb 2000
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From: Temperance,MI
The Better 331?
Hey guys, I have been doing the numbers, instead of a wrist pin that is in the oil control ring 
, run a sbc piston. I have a old old Rods and Customs mag. with this build up before the whole 331/347 deal. Then cut .065tho. off a sbc piston cut the valve reliefs back in it, bored the stock 302 rod to the sbc pin size, and a 3.25 stroke crank Kind of curious what kind of compression that would be with the stock heads. Cam I would run a 94-95 302 cam and do the MAF conversion. What do you guys think? sound like a better 331?
Thanks
Curtis
, run a sbc piston. I have a old old Rods and Customs mag. with this build up before the whole 331/347 deal. Then cut .065tho. off a sbc piston cut the valve reliefs back in it, bored the stock 302 rod to the sbc pin size, and a 3.25 stroke crank Kind of curious what kind of compression that would be with the stock heads. Cam I would run a 94-95 302 cam and do the MAF conversion. What do you guys think? sound like a better 331? Thanks
Curtis
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Joined: Jul 2003
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From: Cincinnati
What length connecting rod would you use? I think they are 5.4 long. One thing I would definitely check is the piston wrist pin diameter against the new rods. To check comp ratio you need to know the combustion chamber volume, gasket compressed thickness and quench heighth. If I had to guess, it would be around 10:1. 89-93 Mustang MAF conversion would be the way to go as well as a custom roller cam.
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Elder User
Joined: Feb 2000
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From: Temperance,MI
Well in the article, they fluxed a 302 crank to 3.25 stroke. Stock rods no 5.4rods, bored the small end of the rod to fit the 350 chebby piston pin. They ran a stupid big cam in it peak tq of 340 from 2200-4600rpm with hyd. non roller and stamped steel rockers on a Edelbrock performer intake and 600cfm Holley.
The one thats in my friends bronco is looking like something pretty ugly happend less than 10k on it and its blowing like it did when the #2 piston got toasted when it was a 302.
Curtis
The one thats in my friends bronco is looking like something pretty ugly happend less than 10k on it and its blowing like it did when the #2 piston got toasted when it was a 302.
Curtis
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Joined: May 2003
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From: south louisiana
Mine's a bored/stroked roller 5.0, cast steel 3.25" Eagle crank, Eagle SIR 5.4" rods, SRP forged flat tops. Canfield heads, Ford Z303 hyd. roller with 1.7 rockers. Intake is a reproduction Ford high rise dual plane 3x2 with 3 Holley 250's. Idles at 700 rpm, power comes on at 1500 and stays to 6500+. Tame enough for the street or trail. With lower compression, it would run on 87 pump gas. Power should be somewhere in the 400+ hp range. Torque? can't tell you but it's got way more than the stock HD Stang clutch could handle. Enough to push the 3800lb 89 Ranger it's in to mid 13's in the 1/4. With all the available 331 and other stroker kits, building one from scratch is a waste of time and money. Can't see the reason for trying to use Chevy pistons, the valve reliefs are in the wrong place.
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Elder User
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From: Temperance,MI
Well I added it up everything included parts, machining costs, just under $1800 including balancing, and using stock heads with the valve job. Talked to my machinist about it said he likes the idea better calls the 302 strokers "the stroker smokers" his kids 331 in a stang burns 1qt every 2000miles. Showed him the article read through it said he was unsure about using the 350 piston too until he read it. So looks like its a diffrent option with crank $215 mains 24, rods 24, rod bolts 55, pistons 174, rings 80, cutting pistons and boring to sbc pin 80, balance 165totaled at $817. Cheapest rotating assembly I have found for a 331 is through the mustang depot built one of them supose to be a hawk crank its a Japanese off brand, same with the rods, pistons Keith black +80 for the rings, and 165 to balance it said and done $127 cheaper to go the other way. I will know how it goes in about a month his kid wants to have his dad build him one he wants to go with more compression no happy with low 12s.
Curtis
Curtis
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Joined: May 2003
Posts: 11,141
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From: south louisiana
The total cost for the short block on my 331 was $1325. That was the kit, and machining. AND it doesn't smoke. Tell you mechanic friend to find out why that 331 is smoking. Could be nothing more than an un-baffled valve cover, with the PCV sucing up the oil.
