changing exhaust manifolds?

I have a 1983 gm 305(228)and I'm going to be changing the exhaust manifolds,risers and and all fittings to y pipe.

I think I've located the kit to buy but I want to make sure its the right kit.
I haven't removed the old ones yet and as far as I can see I need to know;
1.3" or 4" id

2. what size spacer?

3. I have the old "log" style manifolds and I want to go with the center rise that seem to be more readily available, and I've heard these are just a better product.

my question is what are the possible hang ups I might have?

and also when ordering there doesn't seem to be a "year" on the kit while some of the other ones say 1986 & up.

Thanks in advance for any help recieved!!

Dan

Re: changing exhaust manifolds?

You need to make sure of the size.Then make sure the height is the same.
I don't understand the change from log to center riser.It's not necessary.The old works just as good.Your just asking for trouble.Does anything mount to your old manifolds or risers?
Any place that sells manifolds should be able to get ANYTHING you need. Jerry

Re: changing exhaust manifolds?

Thanks for the response jerry,there is plenty of room for the center rise and I guess the reason for not going with "log" type is because in my search for the parts I don't see any of the old style anywhere.

no there is nothing mounted to either side of manifolds/risers.

the center rise seem plentiful pretty much any where I look.When you say I'm asking for problems what could those be?The old ones definitely need to come out tho,they are pretty rusty,the bolts on starboard side holdin riser on are almost non-existent totally rusted.A small leak has formed(I think between riser and manifold.

Did compression check and all cylinders are between 140-160 with exception of one closest to leak 115 on that one.will a leaking manifold/riser be the cause of this?the plug in that cyl. looked ok (no rust)and similar to the rest of the plugs.

I don't mind spending the money but would like to get thru this with the least headaches!so if searching up the old style will work better thanthat is what I will do.
Thanks for your input.
Dan

Re: changing exhaust manifolds?

I changed over to center-riser manifolds on my previous boat, which had a 5.7 Mercruiser. Bought a complete kit and had no problems whatsoever. It came with all the bolts, hoses, fittings and instructions. The only modification, if I remember correctly, was to make up a mounting bracket for the starter slave selonoid, which used to mount on the rear of the starboard manifold; no big deal. Log type exhaust manifolds do have a tendency to cool unevenly; go with the new system. A couple of tips: When everything's off, run through the threads on the block with a tap with some grease on it; clears out all the rust and dirt. Get an extra manifold bolt and cut off the head or get a length of threaded rod to fit. Screw this into the block to hold up one end of the manifold (slide it over the headless bolt) while you catch the other end. Then catch the bolt next to the headless one. Unscrew the headless one, and close everything up. This saves some pressure on your arms. Manifolds aren't light. Carefully if doesn't slip; break plugs that way!. Been there, done that. Good luck and safe boating. Hy

Re: changing exhaust manifolds?

Yeah thanks bookworm all my reading on this subject tends to go for the newer style , center rise mans/risers.This is what I'm going to buy.

Also thanks for the install tip. Iwill be gettin my hands dirty soon.you are correct I do believe I have the solenoid on rear of starboard man.will have to rig something for that.
Thanks again
Dan