I bought a sbc cast iron exhaust manifold (off a mid 80's truck) to install on my 327 I am putting in my 51 chevy. I decided to drop in my mock up motor/trans to ensure my new motor and tranny mount were in the right locations. since the exhaust manifolds on the driver side are usually the problem with fitting a V8 into a stock susp chevy I thought I would bolt on the exhaust manifold and drop it in. Problem. Bolt holes will not line up. thought maybe my plastic mock up motor had the bolt holes miss located. Decided to bolt to the actual motor and they will not fit either. The holes from the outer bolt holes appear to be a 1/4" off (to short). Has anyone ever run into an exhaust manifold shrinking and is there a way to stretch it back into shape (I do not have a torch). I did try using a com- a-long to spread but I am not getting much movement. What are my options.. find another manifold? borrow a torch from someone and heat the shit out of it with the come a-long.
N.A.P.A. (I'm sure any tool truck will have it also.) sells a tool to spread the manifold. It is very common. The tool is inexpensive and works well.
They make a manifold stretching device. I've seen them in summit racings tool catalog. It is placed between the center and out board ports then tightened, allowing you to line up the bolt holes. Matt
Don't get the Harbor freight version it will only last for doing 2-3 manifolds. You will encounter shrunken manifolds often when working on cars so invest in a quality tool early.
Yeah Ken, buy the lisle tool or make your own after looking at theirs. I did not need the tool last time but forget how the heck I got them spread?!
I use ready rod ....thread into the cylinder head at each end, leave about 8 -10 inches of rod out from the block, place the manifold on the ready rod , run it in with nuts evenly and slowly...if ya want warm the manifold up with a torch a bit ...suck it in with the nuts, when it mates the head run the factory bolts in to the adjacent holes...easy
A 1/2" bolt and high nut will do the trick. They finally went to a reinforcment rib to stop that shrinkage.
Yup, heat it up with an oxy acetylene torch and a rosebud tip if you have one on hand. Keeps me from worrying about cracking.
Back in the late 80's our local Chevy dealer just told us to enlarge (drill) the two outside holes...it worked! ie police cars...
Another trick is to simply put in as many bolts as you can finger tight and then run the engine to warm the manifold up evenly and the bolt hole will most likely line up. Put the last bolt in, tighten all bolts.
I had a neighbor with an El Camino that had that problem. I helped him with it, loaned him my Chev manifold stretcher. When we got the bolts started, he got real bold... Told me how his El Camino could give my 63.5 Galaxie a race. I asked him if he had a tool he hadn't told me about. A 'TRUTH STRETCHER'. He tightened the bolts and thanked me. LOL (Merced, 1995)
By the way...How hot do you get the manifold when matching the ports? Can you ever get there again?.... Chevy love. Chevy Volt.
Yea they "shrink". I ground the shit out of the holes and ports for temperarly running them,then pulled them off. Throw them out in the back yard in the dirt. Thats were mine are. Doug Thorley headers replaced them, Great header, super thick flange, never leak or need new gaskets
I just got my Summit tool catalog in the mail today, and as I was reading along in the porcelain library, they have the spreader tool, and it is only 7.50 from them...plus I saw something else from them on their website about free shipping...but you probably have to have a minimum order or some other thing for that....
that is why my tool looks like ( sounds like summit is cheaper than NAPA but I did not have to wait, I got it and fixed the issue). Headers are an option but only Sanderson makes a set to work with the factory steering and v8 conversion. if this manifold does not work, that will be my solution but its alot more money...
It is only certain manifolds that do this. Randy, looking forward to seeing your crew on teh salt this year, you should pit next to us, make my trip for Tecate shorter AND I could man the grill and provide some killer brats at times.
Looking forward to Bonneville too. My main criteria for my pit site is near the porta potty. We need to coordinate sites............
For a minute I thought you guys were jerkin us around. Like sending the new guy to grab a board stretcher after he cuts some lumber too short.