Looking for the spacer that goes between the larger stock exhaust manifolds from TPI's to upgrade my L03 exhaust.

 

Did you find a spacer? I have the right side spacer that goes between the manifold and y pipe from my 1989 L98, I do not know if it the same as the L03.

 

would that the heat riser "spacer"? at least on my 1984 T/A that is the "spacer".

 

The OP is looking to convert his L03 TBI car's low output single catalytic convertor exhaust system to the 1986 to 1989 TPI high output single catalytic convertor exhaust system.

The spacer he is looking for is the one used on all TPI cars from 1985 to 1989 and TPI cars from 1990 to 1992 that had the N10 dual catalytic convertor exhaust system.

The H.O. exhaust spacer he is looking for started off as the casting for the EFE (Early Fuel Evaporation) Valve used on L69 5.0L H.O. engines. When the TPI cars came out in 1985 they used the H.O. exhaust system. More or less the exact same cast iron log manifolds but without the sheet metal driver's side heat stove and chimney to supply hot air to the snorkel on cold start. The passenger side exhaust manifold is more or less the same, but the EFE Valve wasn't used on fuel injected engines. The cast iron casting for the EFE Valve was used as a spacer to take up the gap but had none of the components of the EFE Valve.

The 5.0L H.O. cast iron log manifolds are part number 14071199 & 14071200 and the TPI H.O. cast iron log manifolds are part number 14094063 & 14094064. They are more or less the same casting except for a very small difference in the casting. They are functionally the same and are interchangeable for one another.

I have no idea what the part number is for the H.O. exhaust spacer that was repurposed from the H.O. EFE Valve casting.

Later on, GM went to a cast iron donut gasket style spacer to replace the EFE Valve casting they were using earlier. The part number for the later spacer is 10136863. I have a Fel-Pro part number for a donut gasket that Fel-Pro says takes the place of the GM 10136863 cast iron spacer. Exhaust Pipe Flange Gasket Fel-Pro 61010. It has been discontinued by Fel-Pro, but you can still find them new.

I'll edit this reply and post pictures in a little bit.







NOTE: The exhaust spacer made from the EFE casting is an 1 3/16" tall. Using my precision calibrated eyeball micrometer, I can see that the GM #10136863 spacer ring is nowhere near an 1 3/16" tall.