intake exhaust crossover

[jsf515]

first my problem: on my 63 lesabre's first real trip out after about a year of rebuild and repair, the freeze plug in the bottom of the intake manifold blew out.

my setup: i have removed the thermostat butterfly flap from the right exhaust manifold and plugged the holes. also removed were the tubes for carb choke as i have a new carb w/ electric choke. these holes were also filled. in the intake manifold, i had plugged the exhaust crossover holes at the seat of the carb with pipe thread plugs.

theories: a few of us were talking last night, but none of us with the vast experience of nailheads as seen on this board. it was mentioned that the plug blew out from exhaust pressure. i don't see this happening as there shouldn't be much if any pressure from the exhaust up at the intake without the flap installed/closed (note, nothing was noticed in the exhaust that would create any high backpressure). my thought is that it was just not a real good fit of the plug (althought it seemed tight), and difference in metal expansion after getting the engine warmed up it just fell out. i donno.

question(s): is there a better way to plug the crossover of exhaust in the intake? does anyone make intake gaskets with the exhaust ports blocked? is there a way to assure the freeze plug doesn't blow/pop out again? maybe peening the intake metal over in a few places after its installed?

sorry for the long post. i guess i get a little wordy sometime. any help would be greatly appreciated. i'd like to get this problem solved asap and get the lesabre out on the road again. it was a blast having her out yesterday!

thanks very much, j

[rcull]

Sounds to me like your on the right track.

I have some sheet stainless steel which I have often cut and placed in the intake manifold gasket where the exhaust crossover is. It has been satisfactory.

You could most definitely "stake" the crossover plug to help it resist falling out. It does make you wonder a bit about your exhaust system. Much backpressure, is caused by too small an exhaust system or could your mufflers be plugged?

Good luck

[jsf515]

i have found and ordered intake gaskets with crossover blocked off from postons. was gonna do the sheet metal trick like you mentioned, but i found these, so i'll give 'em a try.

thanks for the reply.

j