Ok, so here’s the update I promised on a couple other threads. 383 to 432 (431.92 should be called a 432).
I have always been a 383 fan, since my high school 383 RT. I’ve been motoring a ’73 Challenger with a 383 I snagged several years ago, and it’s been a really good build.
You guys, all the articles and motor-candy available these days got me to drooling. But I still wanted a 383. So here I am, many dollars later, and anxious to play.
383 .030 over, 4.28 bore, stock deck ht.
440Source 3.75 crank (stock 383 journal sizes)
Diamond 51910 forged pistons
Eagle 6.358 rods (mopar pins and mopar journal sizes)
440Source Stealth heads
Lunati 703 hyd cam
Crane 1.5 adj rockers and Crane timing set
6 qt. hemi oil pan / 1/2in. pickup / HV pump
Mopar alum dual plane intake, notched for cross feed (reuse)
Holley 750, 72/80 jets, 6.5 PV, medium vacuum spring (reuse)
Dougs 1 3/4 headers (reuse)
21/2 pipes with Dynomaxs (reuse)
The block : a lonely December 1965 383 bare block found on Craigslist for $160. Fairly clean, and std. bore. Took it to .030 to avoid the extra cost of custom pistons. Decks were checked to be straight and we left them alone. Crank bearings, same thing, did not align hone for no good reason. The factory was running good that week.
Stealth Heads: I ordered the upgraded springs, locks, retainers, and guides for durability. Heads seem to be thick in places where it counts. Biggest headache was the pushrod holes were not aligned on the intakes (could not align 3/8” pushrods to the lifters and 1.5 rockers) – had to burr them to lower the guide hole which runs through the meat of the intake runner walls. Block facing plane was not perfect – had a .0015 negative curve in them, which the shop said comes from using a grind wheel too small for the job. Had the shop take off .003 to clean them up, not enough to change the chamber size estimates. Did not CC them, but they looked fairly uniform to the eyes. Spring height - as groups, was very uniform for intakes at 1.885 and exhausts at 1.890. That’s not really all that relevant with my adjustable rockers, but I thought I’d report what we saw. Spring pressure – 320 open / 140 closed – a nice upgrade. Seat check - sampled one cylinder and it was perfect.
440S Crank : We were very impressed with the 440Source crank. I did not buy the fully pre-balanced 440S kit, so balancing was on the agenda. Nice edges, chamfered oil holes and bearing sides. The shop liked the oil channel chamfers especially. When they balanced and had to add metal, they said it was among the hardest they had ever seen. One plug of Mallory. When the shop finished, it was left at -0.58g left and -0.89g right.
Diamond pistons : the 51910 piston is designed for the 383/400 rods. I went with the shorter rod on purpose, so please, let’s not debate the ages here – R/S at 1.7 is a good space. 1.72 CH, good skirt length and pin placement were considerations. Eagle rods with stock journal size and ARP bolts don’t really need any comment.
Assembled : The rotating rod bolts cleared the cylinder bottoms, but it was very tight, so we cleared them a smidge extra, like about 0.125. ARP studs on the bottom. This set-up, with stock deck height, showed to have pistons in the hole about 0.033 all over. I matched that with an .025 three-layer steel shim to have some aluminum head shift allowance, with total setback in the .05 to .06 max alleged sweet zone. Everything came together with no issues. The overall stack adds up to 10.02:1 compression. The 6 qt. hemi oil pan fits an E-body with no issues, and keeps good gnd. clearance.
Cranked : The motor sounds super nice, and it sure feels like the balance is right. And whiz-bang, there’s no nagging forged piston clanks or rattles top or bottom. It runs quieter than the 383 did. Previously I was running the Lunati 702 in a 383, and the 432 might have swallowed the 703 with about the same behaviors, but eau contraire…. Installed straight up (with the built in 4 deg adv), it lost some serious vacuum and seems to be a young pissed-off pit bull at idle. Runs about 10.5 vacuum but, good enough, the brakes and heater / AC valves work too – but I can always let off the gas to switch the heater air valves.
And, I got the FBO limiter plate for the distributor because the 703 appears to like 16+ initial to get to 34 advance. Runs good, idles as well as we could expect, with the vacuum advance hooked up.
Took 12 months to pull it together from the time I found the block on the web. After a couple weeks of prepping (that’s means waiting for parts) and tuning, today, I actually drove it. Pulls like crazy, idles good enough to attract attention, and runs very smooth at the highway rpms of the 3.55s. After about 50 miles of checkout and a lunch run, I checked a plug, and sure enough, the 750 set for the 383 was a bit lean for the 432. I added one more number in the primary jets to see I can darken the plugs just a bit. The moly rings in the properly prepped cylinders seem to have seated quickly. This thing runs great, pulls like a beast, though I haven’t yet really pushed it. I confess the 383 saw 6400 a few times and that felt a bit much (yowzerz!) for my street ride. I now run the FBO ECU with rev limiter at 5600. I ran about half the Power Tour a few years ago, and this year I plan to run it all. For me, I don’t need a taller intake and porting jobs that won’t really benefit the motor until 5800. I’ve spent a lot of time pitting Super-Comp at the track, and watching poorboy money get left on the line. Not my thing. I know that the rest of the car – tranny and rear, are not built for what this thing can tear up. But I’ll work on it. I am also aware that the 750 carb will top out at 6000 on these cubes. This one will be fun in the climb, and will sound like Mopar evil when crawling across the cruise-in lot on Saturday night. So far, this is a sweet build for my personal fun factors.
