i have a 58 348 that a want to do heads on... i was given a fresh set of 61 heads.. knowing that my motor was sort of a one year because of the water flow ,, will the 61 heads work,, or will it restrict the flow
Jump over to www.348-409.com and the experts can tell you what to do. You will need your casting numbers so they can see when the block was manufactured and if it has the spark plug cooling holes. The very early 58 blocks did not have the holes in the block, the later ones did.
No, the water p***ages on the head will be open, engine won't hold water. I don't know if you can plug the extra p***ages in the heads and run them or not, but you might look at it. Larry T
OK, I did this on the Touring. Early 58 will not have the steam holes and extra meat for the later heads. Late 58 blocks "should" have the meat since they made a running change. You may be OK w/o modifying anything. What I had.........early block, 60 or 61 heads. the steam holes in the heads overhang the block aprox. 1/16" or a little more so the coolant will run out, dont ask me how I know this! took my heads and ground out the casting a bit in the steam holes. Pre-heated each hole with a torch and welded up the hole BELOW the deck surface. To be safe I put a blob of JB Weld on each one in case there was any porosity. Car has many miles on it and has never had any issues with the modification. I did this on ***embled heads and did not need machine work. You could do the work on bare heads and then surface them but I see no reason to get that carried away since most of the hole is outside of the actual deck. Before welding I looked into tapping and threading in plugs. I did not go this route since the holes are odd shaped, kinda an oval and plugs would not work. Hope this helps.
I've got some 58 heads that I would trade for later model heads, but shipping would probably be killer. Larry T
Guess the early 348's were known for letting off steam! Too bad u could not harness the steam and convert it to energy ala steam engine. Guess Chevy went by the trial and error designing methods back then. Probably doesn't have a camshaft thrust takeup plate either.
Could have been an "o ****, we have no cooling outboard of those plugs. Jim I thought YOU were on that!?" sort of slip through the cracks deal
If Chevrolet wouldn't have upgraded and improved their production engines, there wouldn't be any 4 bolt blocks, 2.02 heads,................................ you get the point. All manufacturers improved their production engines as the found the weak spots. Larry T
If my memory serves me right, Chevy made some plugs for the later heads on the early 58 engine. The part number for the plugs were in the 59 shop manual supplement.
When I did mine I gave a 348/409 guru my block number and he sold me the right heads. Said my early block was different?
Being the current owner of the engine Tman is talking about I can say that it has had no problems in the 4500 miles or so that I have driven it.
I doubt that, would love to see them because the steam holes in the heads are all a different shape/size and rather rough cast. I first looked at drilling and tapping them but they were not uniform for any type of plug I could come up with Krylon, read my reply above. the early block has no meat in that area and the holes in the heads hang over the edge of the block enough that coolant will run right out
I don't know if it was factory or not, but I had an early 1958 348 engine with late 1959 heads on it. The steam holes had been drilled and tapped, with tiny pipe plugs installed in the holes. I never had the engine running, (it was bought for parts), so I don't know first hand if this fix worked or not. However, the guy that I bought the engine from, said that he ran it in a Model A for several years.
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