Hot Rod Forum banner

346222 18 RH exhaust manifold

4K views 4 replies 3 participants last post by  MI2600 
#1 ·
Hi I'm new here, have a rodded truck 3/4 4x2 1981 sleeper worker and wondering about the heat under teh hood coz it's killin for a rebuild

the topic number is the exhaust manifold from the engine right side (duh)... I've been told it's from a 307/327/400 series of engines, and need to know if that makes it compatible to 305 exhaust ports. The biggest reason for this prob is I have a plug prob and the dude who sold me the truck isn't the brightest, telling me it's a 305 etc, and the parts say otherwise... I can't get at the rear vin when I tried it's covered in crap, the cleaning action made me mess my timing, wrecked a day for me in tuning carb and timing again, and blew a half tank of gas and some plugs. I could remove the head covers, but it's my worker and I'm trying all other resources before I start stripping too much more...

So is it compatible with 305 350's???

And should I change plugs to the longer threaded 327???
307???
 
#2 ·
they are interchangable. rams horns are the best cast iron kind they made them in 2 inch and 2 and half inch collector. you can buy new 2&1/2's somewhere for $100 ea. or pay the same for them used. If you don't want to change your exhaust ($60 or so) use whatever fits.
As far as plugs I use whatever Autolite calls for. I know their made by Ford, but everyone I ever knew swears autolites are the best plugs for a SBC. Been usin 'em for 25 years and never had problem one. They never foul unless you gots serious problems.

[ August 08, 2002: Message edited by: bullheimer ]</p>
 
#3 ·
My reference book shows the 346222 to be a '73 to '80, right side, manifold for the 307, 350, 400. They're probably the "under the plugs" type exhaust, i.e. shaped like a large "W", not a ram's horn. I think (and that can be dangerous) the 305 heads had a different bolt pattern. Look to see if the heads have seven bolt holes for the exhaust. The older style heads had a six bolt pattern. I know that, twice, I have replaced a 305 with a 350 and found the manifolds for the 305 don't want to cooperate with the older 350 heads.
As to your engine's identity, see if you can get the stamped number which is located on the small flat pad on the block in front of the right side head. It's probably hidden behind the alternator. The important thing is the 2-3 letters at the end of the number. This number is more accurate in telling the origin of the engine.
 
#4 ·
well i could have sworn the last set of heads i took off my 350 were from a 305 and they had the same bolt pattern. so now i hope y'all are confused as well.
I don't see any way that a sbc could have more than six exhaust bolts. it would have to go between the two center ports.

[ August 08, 2002: Message edited by: bullheimer ]</p>
 
#5 ·
Some of the Chevy heads had seven holes, but you only used six. The difference I was talking about is the last bolt one one end. If you look at a set of exhaust manifold gaskets you'll see that one or both of the end gaskets have an extra hole or notch. This is to accomodate the different pattern.
There may have been different 305 manifolds, but last weekend I dropped a temporary 350 in my '86 El Camino and the last (rear) 305 manifold bolt hole on the passenger side doesn't come close to the hole in the #441 head. Header time!
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top