I’ve just installed a set of Flotek 101-505 cylinder heads because of a small leak in the head gasket. the engine is a good quality crate engine. there was a double mosfet radiator fan failure and the engine got overheated then developed a fine leak. it came with angle spark plug style heads, like on my 91 tpi, but perimeter bolts. I wanted to have a good spare to swap quickly and to revert to center valve cover bolts but turned out the corvette valve covers would not fit. Not a big problem because they have perimeter holes as well. …Just some context to explain my choices.
But now the real problem is the spark plug holes although angles left/right away from the headers tubes they also point down. I guess those work with cast iron ram horns c3 that are mounted above the plugs. In the pictures the threaded holes look normal like on the l98, anyway I though there were only two versions: straight and angled.
What do you think I should do.?
I could resurface the original ones and remove the Flotek heads put everything back or make some custom headers, if that is even possible
there are also aftermarket headers that work with corvettes but not sure which ones would work?

my stock headers also have multiple repairs and might be fragile at this point so new ones would have some advantages like, would be more reliable, flow better and compatibility with both sets of cylinder heads.
thanks

 

Most L98 engines/heads have angled plugs for header clearance, and aftermarket headers are usually configured for angled plugs.

ARH headers on 1984 C4 and most will be about the same:

 

this is the datasheet
Thanks. your engine looks fantastic
these Flotek 101-505 seem to be a bid different and since the spark plugs get to close to the exhaust tubes, even with the heat shield removed, it is possible to have the same issue with other headers. I've called an exhaust specialist and he said he could modify or build new ones.
the exhaust hasket is slightly thicker, made of aluminum sheets, I suppose that shoudn't be a problem

I think I'll just resurface the original ones that came with the engine and put them back. these Flotek should've fit but maybe they are not that reliable and not worth modifying the exhaust for them.

 

Hooker Headers work much better with Angled Plugs than Straight. I have been battling Straight Plug AFR 195s for years and just switched to Angle AFRs.

 

thanks. I will put the heads old back. the stock system is easier to live with than with long tube headers. I also need the air system for MOT. My stock manifolds also have v-band fittings at the collector and it is easier to work with .
the old heads have angled spark plugs holes but they are also compatible with stock manifolds. next time I will probably buy the same heads as a spare, since they are angled correctly and don’t have other issues