Hot Rods SBC casting info needed for angle plug engine

the vk231800 is in my roadster, told it was a 283... or 327... it has the oil fill in the manifold.... but you can do a lot of them that way...on the rear block casting number they put a terminal block covering the numbers... another reason I think that this car had a differant body before,,,,

 

First design angle plug heads were 492 castings with heat crossovers. These were the same base castings as the 492 castings used on performance engines in 68 or 69. The angle plug versions were available by 1970.

The 292 casting angle plug heads were first available about 1973-1974, and had no heat crossovers, and also were machined for larger diameter springs, 1.4-ish diameter. They were often also called turbo heads

Around 1980 Chevrolet released another angle plug head, casting number ending in 034. Again this head was a race head, with no heat crossovers, and big spring pockets machined by GM. Chambers were nominally 63-64 ccs. And that's the end of my experience with factory heads until the Aluminum Corvette heads came out in the late 80s. I think the pre reverse cooling heads numbers end in 127. They also have no heat crossovers, not needed with mfi. But they use slightly smaller valves as I remember. I think the exhaust valves were 1.55 and the intakes were 2.0. But they also have smaller combustion chambers, good for bumping up the compression.

And aluminum heads tend to be able to run a full point higher compression compared to the same chamber in cast iron, due mainly to the thermal characteristics of aluminum. There's less tendency for preignition and detonation.


I was building a 327 up and planned on using a set of those heads with the Hilborns back in the mid 90s. Sold the castings before I got around to it. Brand new castings, but I ended up moving to upstate New York from Ann Arbor Michigan... oh well

 

Dave, the 1968 hi-perf heads were still the old style camel hump castings, the 69 and later small blocks used the "accessory bolt hole" castings.

 

Yes they were available in the 70's I believe 73 are when mine were made.

I doubt they make much more if any HP with flat top pistons . I think thye were intended more for a pop up type piston. There good for bragging rights now a days as a set of $400 Ebay aluminum heads will out flow them as well will the Vortec heads .

I'm contemplating putting my set on a 383 but honestly with 64 cc chambers Id need dish pistons to run them and be 10-1 and im leaving HP on the table over a cheap set of aluminum heads that will allow about a point more of compression ( so they claim ) and a weight savings also . They may go on a 327 also but the headers on that car will not fit them .

For the to really make good power even back in the day they needed to be ported and then there were several types and the early angle plugs were not the best compared to the later ones.

 

Hey I'm old and lazy. Didn't pull up anything on the internet, just a fuzzy old memory... seriously tho, good information about the dates. I was still in hs when I bought the 1st set of 492 angle plug heads. They were like gold to me, all newly machined. It was 1971, and I was collecting parts for a new engine for my limited class 57 Chevy dirt car. That engine never made it into that car. I know you'd like it, however. 327 365 fitted block (okay so it was going to be a little big... I figured I'd be a backmarker, so never get checked for displacement). All the hi po parts that went with those heads. Then the 140 Offroad cam and edge orifice lifters. Z28 pan, pump, pickup, and windage tray. 1st design Tarantula intake, 850 double pumper, Corvette dual point tach drive distributor w/o vacuum advance. That engine would pull to 8200 rpm. Crank was from Moroso, indexed, 10/10 under. Wish I could reproduce it for the Whatever project. Probably a good thing I'm going to put a 283 together for now...

 

It was always my understanding that they were basically fuely heads with angle plugs . The 292s are a thicker casting to allow extensive port work without hitting water they also are machined for bigger valve springs.

 

What is the best carb to run on a 292 headed 350 chevy, holley 650? Quadrajet?

 

Yes to all of the above. The 492 castings were the same as the ones used on the LT1 350 enginne up to machining the sparkplug holes. A point of interest, a couple of the head porters offered a service that plugged the original holes in heads back to the 461 heads and remachining for peanut plugs at the angle. Just in case you had a lot of money in older heads that were otherwise still good.

Like lumpy said, the 292 castings had more iron in the spring seat areas, the deck surface, and the ports. This allowed for bigger springs, more creative porting, and probably the best feature, angle milling the heads to get smaller chambers and better angles on the ports and valves. The 492s could be milled to reduce the valve angle from the stock 23 begrees to about 21 degrees max (or min, depending on the point of view). This moved the valves away from the cylinder wall, and also stood the intake ports more upright, helping with flow.

The 292s could be angle milled further, but I don't know how far, as they have thicker deck surfaces, allowing deeper cutting on the plug side of the heads.

The 034 heads have even more iron in those critical areas, but by then aftermarket heads were starting to have all of these features and more. The 400 engine that ratrodder has, has Gaerte spec Brodix heads from the mid 80s that are big enough to feed a good big block. And they are now considered antique. The last iteration of that engine before the Rodec 350+ block had one too many heat cycles, it was 14:1 compression on methanol, roller cam that the lobes don't look like eggs, they look like squares with the corners rounded off, and all of the stuff that good sprintcar engines had. And somewhere over 700 hp. And it wouldn't be competitive with engines today.

I was always amazed at how tight it wanted to rev, given the 3.75 stroke. It saw about 8700 a couple of times in Jim's hillclimb car in the speed trap at Mt. Washington. And I could get it to idle at 1100 rpm! But it didn't start to really pull until 5000. What a beast!

 

It looks like you basically have an LT1 . that intake is a square bore and wont take a q jet without an adapter. The factory Lt1s and 302s came with a 750 vacuum secondary Holley , thats what I would use personally.

 

Depends on what your doing with it .
If its a street car your not all out racing not taking it to 7000 rpm or what ever and the cam is not huge Id run a vacuum secondary 650 Holley or even a Edelbrock ( if you can stand the looks ) If your race in it with a big cam and running it at very high RPM Id go 750 Holley style mechanical secondaries with 4 corner idle adjustment and adjustable stuff . .

Even a simple 600 Holley vacuum secondary carb with only idle adjust and ability to change jets on the primaries will run surprisingly well on a 350 and you might not any real HP change until you get the revs way up . I have one on a full size square body with a cam and head good heads and its all it really needs for the street . IMO