intake manifold ?

[popsthebuilder]

Broke off the stud on the left side of the thermostat when I was trying to change it a few months ago. Tried vice grips. Drilled through and attempted screw extractor. Split stud. Broke off flush w/ manifold. Tried extractor again. Decided to tap stud. I was careful, and backed out the tap, and was using a small wrench as to not put excessive pressure. However I still managed to break the tap off nearly flush. I don't think there is any hope now, so my question is... Would an intake manifold off of a 307 of the same era bolt straight up to a 73 350? Also, would any 2 barrel work? Thanks in advance. Looking for the cheapest temporary fix.

[77ChevySharkBite]

Do you mean 305? If you were to find a 73 intake it would bolt right up no problem. As far as a 2 barrel not sure why you might want one on a 350, but I would imagine as long as it was from a GM vehicle it should match up fine.

If you were a lot closer to me I would be able to help out with a carb and intake as I just put a new ones on mine.

[INSIDIOUS '86]

Did you try chipping it out with a chisel yet. Stud extractors are brittle and that's a good thing when they break so its possible to get them out still. I have also used chisels to chip broken bolts out bit by bit out of the hole then drilled and helicoiled to repair.

In extreme cases on rare manifolds you can use a torch to melt and blow out the broken stud and extractor some then drilled and tapped. Not easy to do without melting the metal around it to much

[Dead Parrot]

A manifold off almost any SBC should work, even a 307. Almost any carb should allow the truck to move under its own power. Just don't expect neck straining performance. Watch the linkage issue. Not sure when they made the switch from direct mechanical linkage to cable.

[popsthebuilder]

Thanks for the quik responses. I'll have to try the chisel. how hard or tme consuming is a swap to a 2107 I think. edlebrock?

[77ChevySharkBite]

Very simple just a matter of unbolting your current carb and the accessories on it I'd say salvage them and then just put the new one on, you'll need an adapter for it though. Other than that very easy swap.

[popsthebuilder]

it is supposed to be an oe replacement. would I Still need the adapter fer the rochester?

[77ChevySharkBite]

Originally Posted by popsthebuilder

it is supposed to be an oe replacement. would I Still need the adapter fer the rochester?

sorry for the late response its an OEM replacement but you would still need the adapter for the rochester.

[dieseldawg142]

if your going to run 2 bbl, i wouldn't spend the money on the edelbrock. kinda defeating your purpose, good flowing intake choked by a small carb
when i snap a bolt, i keep drilling it bigger till hardly any bolt is left, then i use the easy out. same problem as you,had a few extractors snap
cheapest? throw the 307 intake on, it will fit, but runner volume is designed for 307

[popsthebuilder]

Decided to go with the new 2701 edlebrock (only one in stock) with a Mr gasket adapter. will the linkage bolt up w/ out modification? Someone told me a carbide bit would drill through the tap. Guess I'll save the intake. Later down the road, would the oe manifold off of the 350 work on a slightly hopped up 307?

[INSIDIOUS '86]

Why two barrel though? For originality?

[77ChevySharkBite]

It should work fine just make sure you keep all your bolts together and keep tabs on what goes where, it should be fairly simple. Make sure you remember where your distributor gear is sitting like that has to be as close if not dead on. It's going to be tedious work but it can be done and if you need help were here for you.

An 350 intake will fit on a 307.

[popsthebuilder]

I was asking about the 307 w/ 2 barrel because that is what is in my 72. 73 is the 350 with the tap broke off in the manifold. Was thinking of swapping. New plan now though. Thank you all for your support and insight. I will post once I have made some progress of destroyed more stuff that has survived for over 40 years.

[Palf70Step]

Get the number off the stock manifold and check you junk yards. I believe the 2bbl manifold is the same for the 307/305/350. Just compare the one you have to the one in a wrecking yard. I know there is quiet a few spots around Baton Rouge area that you should be able to dig up a manifold for next to nothing. Most folks are chucking the 2bbl.

[popsthebuilder]

There is an insane amount of what I guess is carbon build up sitting on top of the block. It seems to be covering some weep holes or something. Should I try to clean that or at least expose the holes? How would I keep it from going further into the passages. I'm completely green at this so a lot of stuff isn't obvious to me. thanks again.

[77ChevySharkBite]

Best thing to do is clean it all as much as possible dirt or anything doesn't have to be spotless but make it pretty close to that. You really don't want anything falling into the block.

To keep it from going further in I would say do 1 of 2 things either 1. get some paper towels and just kind of plug it up so nothing goes in or 2. use pieces of tape and do the same thing just be very careful when scraping off carbon.

[popsthebuilder]

Gasket instructions state that my year is supposed to have a restrictor plate. /would that be for emissions? it's a 73 3/4 ton so it didn't have emissions regulations.

[77ChevySharkBite]

Um.....that I have no idea on that honestly, I would say make talk to your local parts store or maybe give a GM dealership a call.

[Dead Parrot]

If you are talking about the gaskets between the manifold and the heads, there is an exhaust crossover passage under the carb on the intake. There is a rectangular hole in the gasket that matches the passage. The gasket kit should include a pair of blocking plates for the holes. I think the OEM thought was the exhaust heat would help with vaporizing the gas, improving emissions and economy. Downside is too much heat warps the carb. One common solution is to block one and leave the other open. A lot of folks just block both.

[motornut]

Originally Posted by popsthebuilder

There is an insane amount of what I guess is carbon build up sitting on top of the block. It seems to be covering some weep holes or something. Should I try to clean that or at least expose the holes? How would I keep it from going further into the passages. I'm completely green at this so a lot of stuff isn't obvious to me. thanks again.

I scrape using a shop vac,then tape over holes,clean up residue before installing

[popsthebuilder]

I just can't win. Finally got manifold bolted down. The whole reason I switched out manifold is because of broken stud in thermostat housing that also holds alternator bracket that bolts to water pump. switched to hei and immediately blew water pump gasket out. replaced pump, same thing.\, so I concluded that the broken stud was at fault. put original pump back on truck. It started leaking before anything even got pressurized. Rerouting the vacuum for brake booster caused more problems. Interferes with alternator bracket, and fuel line. Should I replace back plate gasket on original water pump, or just try another bs duralast pump? What could I use to make a tight 90* turn directly from the intake manifold going to the brake booster? Thanks everyone?

[Dead Parrot]

Brake booster vacuum is normally taken from either a port in the back center of the throttle plate on a q-jet or from the port just behind the carb on the intake. The OEM solution has a bent tube. If you don't have the OEM tube, just get a 90* fitting from a hardware store.

[popsthebuilder]

Finally got everything taken care of. Thanks for all the help.