RAMBOW

Not sure what to call these things.
Big iron? slugs, somehwat formed to fit in the exhaust crossover port in the cylinder heads.

I got them about 10 years ago when i bought a performer intake for another car.. didn't use them, but never tossed them for some reason.

Was grinding down the AIR bumps in my heads the other day and spotted these sitting on a shelf. Started filing and got one to fit about 99.9% into one of the heads.

Does anyone run these things? Do they rattle or cause problems?

Rickman48

The sheetmetal ones burn-up rather quickly - there used to be some with a 3/8 hole in them that was supposed to help, too, but those burned - out in a month or two.
Only sure way is to pour molten metal in them, and to grind smooth the ports on the exhaust port.
Any leakage will begin the burn-through process.

RAMBOW

I know the sheetmetal ones suck. I'm referring to these:
Edelbrock PN# 2733


Anyone use these?

bigD

i'm gonna use a pair of them. i have read of people using them and being happy with them... i may drill 1/4'' holes in mine as it's going to be a street engine and i want a little heat to get thru...

74 Omega

I used them. After grinding and shaping and installing with a BFH (big f*%king hammer) I had to remove them. They made so much noise it was embarrassing driving around. After the advise of this forum, I decided to not reinstall them, I was told unless you plan on racing not worth it (paraphrasing).


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74 Omega

Look at post #6

https://classicoldsmobile.com/forums...-manifold.html

He's a smart man...I will usually take his advise...

1971

I just installed some in my heads, you need to file them down a bunch. I had heard they might rattle, talked to a few people and came up with this.... Sounds a bit shady but these were pretty experienced motor guys. File them so they sit flush, then regular ( not quick set only good to 300 degrees) JB weld. That stuff is good to 600 degrees. So i just coated the plug and placed it in. Then smoothed out the area let it dry and sanded flat, looks pretty clean even. I let you know if they rattle.

bigD

that certainly has me rethinking using them... for as much fitting as it is taking to get them to fit the last thing i ever thought i'd hear bad about them was noise....

any reason they couldn't be brazed in?

droldsmorland

I welded them into my iron intake 10 years ago and counting. No noises! I removed the flapper in the drivers side ex manifold and welded the holes. 400s as cold blooded as hell until its warmed up completely it but resolved all my heat soak hard start problems. Summer car only so not an issue. Had to modify and adjust the divorced choke to a very light setting. Of course if you have an aluminum intake or heads the iron plugs wont work. In that case find someone to widdle you some out of aluminum and weld into the intake or at least tack weld. If you do need some choke action convert the Q-Jet to an electric choke.

bigD

i think i'm gonna go ahead and fit mine to the heads then drill a 1/4'' hole thru them to get some heat to the intake for atomization and then have them brazed in.

67Olds442X2

I shaped mine with a bench grinder to get a good fit. No noise problems yet, on the second go around. Did a second pair on my rebuild.
Takes awhile to get the engine idling good on a cool 40 degree morning because of the lack of cross flow. Kind of fun watching the exhaust as it warms up, has a tendency to blow smoke rings.

RAMBOW

I think I'm gonna bite the bullet and fill em with aluminum. I've been reading up on it and it doesn't sound like rocket science- And you really don't get any extra benefit from using those plugs other than the temperature, than you would by just blocking off the port w/ a peice of steel over the opening- whereas filling the port and totally separating the two exhaust ports from each other actually helps several things, as well as preventing heating up the carb.

as for the atomization thing... Really? So are edelbrock heads race only items then, since they don't include an exhaust crossover? How about all the performance manifolds out there- (RPM airgap anyone) that don't have crossover passages?

There are things that were designed a certain way to help these cars function great in all conditions as daily drivers. Things to make it so your grandma could hop in the car and drive it. Talking 45 years ago here.
The way the vast majority of us drive these classic cars today- we are more than willing to put up with some minor annoying behaviors to gain more hp.

If you are going to drill even a small hole in your crossover block, don't even bother blocking it. you aren't gaining anything at that point.

captjim

I could be mistaken, but I believe those plugs are meant to fit in the intake, not the head. I have fitted them into SBO heads with no issue.

bigD

i just finished fitting mine to the heads... as tight as they fit i cant imagine them rattling but i might see about getting them brazed in.