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Old 03-22-2020, 12:28 PM   #11
MikeB
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Join Date: Jul 2000
Location: North Texas
Posts: 3,672
Re: Small block 400's???

Found this on another forum written by a guy I know and respect:

DO NOT USE ANY STOCK 75-LATER CHEVY HEADS ON A 400. In 1975, Chevy started cutting corners on their heads to save a little weight. In 75 the heads had a second exhaust crossover port added which produced more head heat. And by the late 70s, all SB heads (except the Bowtie heads) were light weight, thin wall castings. ANY machinist who has lots of experience with SB heads will tell you that Mid-70s and later heads are either cracked when they come in, or, they probably will crack soon.
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Mike
1969 C10 LWB -- owned for 36 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, recent AAW wiring harness, 5-lug conversion, 1985 spindles and brakes.
1982 C10 SWB -- converted from 250-six to roller cam 350, Vortec heads -- sold
1981 C10 Silverado LWB, 305, TH350C -- sold, but wish I still had it!
1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming.
Retired as a factory automation products salesman.
Worked part-time over the years for an engine builder and a classic car repair shop.
Member here for 24 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then!
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