I bought my BBC 502 several years ago from a guy who apparently abandoned his project, so I got a screaming deal on it. It was a new, never run, deluxe GMPP ZZ502 crate engine kit he bought without the intake and carb or distributor. When I got it, an aftermarket single plane intake had been installed as well as a cheapie HEI. I sold the intake and distributor and started collecting parts to make it a Ramjet 502 which is the fuel-injected version.
The GMPP Ramjet 502 crate engine has the same internal parts as the ZZ502....forged steel crank and rods, forged JE pistons, aluminum heads with 2.25" intakes, and a steel hydraulic roller cam. The only difference is the Ramjet is EFI and the ZZ502 is carbed. I won't ever have another carbed car engine, so I found a brand new set of Ramjet manifolds for sale locally and bought them, and collected all the correct sensors and other pieces from various sources. I bought the fuel rail, regulator, GM computer-controlled distributor and other parts from GM Parts direct and a new Holley dual 58mm throttle body (stock is dual 48mm), 42 lb/hr injectors, and Commander 950 Pro EFI controller. I am using an MSD coil, stock GM plug wires and stock AC Delco plugs. The final upgrade was a Holley wide-band O2 sensor kit that interfaces to the C950.
The engine was shipped to me pretty sloppily and the oilpan and valve covers sustained some minor damage so I'll need to address that. The exhaust ports were left uncovered and no spark plugs were installed. I put the engine in my frame as I was building it and tried to cover the ports, etc. After years of sitting I decided to tear it down for a cleanup and replace the low-tension oil rings that GM put in these engines that sometimes cause oil consumption issues. There was actually quite a bit of trash in the engine so I'm glad I made the decision to tear it down.
The past week I completely disassembled the engine and took the block to a local shop for a torque plate honing as recommended to my by Total Seal. All the parts I took out looked really good and are laid out on my assembly table. I took the pistons I removed, as well as another brand new set of OEM 502 pistons that I bought when I planned to build my own 502 just in case they needed one or two for a better fit.
When I get the block back I will document the assembly process here. The shop will be removing the cam bearings and all oil galley plugs. Then they will install the new cam bearings and plugs after honing and cleaning the block. I will be installing the crank with the same bearings it came with, a new rear main seal, the same rods and bearings, and the same pistons with a new Total Seal ring set containing standard tension oil rings. I'll order the rings when I'm sure they successfuly honed the block and the pistons fit.
I haven't decided whether to upgrade the cam to something a little bigger or not. I like the sound of the stock cam, but there's a lot of hidden power in the engine that a cam upgrade can release. The valve train can handle quite a bit bigger cam. I will be using the stock GMPP timing gears and chain that I removed. All new seals and gaskets will be used.
On the top end I won't be doing anything to the heads except using new head gaskets (same as OEM) and will probably install a set of roller-tipped rockers with the stock pushrods. I'd like to do full rollers but I want to use the stock valve covers and they won't fit. I like the stock covers and don't want to change them. I will have to machine the upper intake manifold to accept the larger dual 58mm throttle body, since GM thought it would be nice to just make two 48mm holes in it.
I haven't built an engine for several years except rebuilding the top end of my ATV, so I'm looking forward to doing some actual wrenching on this engine.
I posted these on my Nomad chassis assembly thread but decided to post them here too. These are a few pics of the teardown.
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