New bolts are always a good idea,cause there's no other nightmare like a broken man.bolt.I would scuff both mating surfaces with a flat file and bolt em' right up no gaskets.I only used gaskets if they did leak after this.Glen
Several of the holes in the hp manifold that slide over the studs are deep. There is no way to secure the manifold without the long nuts. I'm 99% sure the stud length is the same so you should not have to change them. The HP manifolds will not hook up to the log manifold exhaust pipes as the HP exits are 2.5 inch dia and the left side will most likley be pointing at the wrong angle to even be close to hooking up. I don't have a feel for what power gains you may get, but changing to free flowing manifolds and larger pipes can't hurt.
Joined: Thu Jul 06 2006, 12:51AM
Location: california
Posts: 143
Well i have to replace my exhaust anyways, its rusted and its running strait pipes w/out mufflers...which is way too loud. I also don't want to spend an arm/leg for shiny performance ones, so the HP ones were reasonably priced ($50 pair). I guess i should order that stud/nut kit as i expect something to break, and from what you said, the nut is a deeper. I don't really think im going to get a huge difference in performance, but it might flow a bit better, maybe get better fuel mileage?
Joined: Thu Nov 24 2005, 07:29PM
Location: So Cal.
Posts: 1111
That kit looks like the correct one, and the stock stud length is fine. Check your local dealership though. Last time I bought them (years ago) the long ones were around $3.50/ea so you could save yourself a lot of money by checking out the local Dodge parts counter.
I bought a disk brake conversion kit from Tallzag at Spring Fling. Forget him, I could have bought one cheaper from Scarebird online even at his "Closeout" price.
NEVER forget about the dealership. Pie plates, bolt kits, ball studs (for 4-speeds), all bought at the dealership for less than anywhere else. Unfortunately our Dodge dealer left a few years ago. I miss that connection.
*edit* The engine will love those HP manifolds, too. It definitely breathes better than the logs by a lot. With a bigger aftermarket cam, you'd notice it more if you went from logs to HP's in the same day.
i use a gasket because i hate exhaust leaks and doing it twice.you can always cut off the exposed part of the gasket between the ports after it is tightened.the more power the motor has the more of a difference it will make.i am guessing 10hp.it should give you a little more rpm(and rev quicker)due to less restriction.
Joined: Thu Jul 06 2006, 12:51AM
Location: california
Posts: 143
I got all my old manifolds off and exhaust today...not too difficult. I found a crack in my old manifold, and a few loose bolts which couldn't be doing anything any good. I mocked up my new exhaust routing and going to start welding up the new exhaust little by little. I hope all the work is going to pay off, it looks like its going to be alot more work than i thought!
I have the HP Manifolds on my 383 in my 66/300. What ever you do, do not run them with a gasket. You will need metal to metal contact when it comes to the long nuts for those manifolds. Have a machine shop take a lite swip across the mounting surfaces and make sure your head mounting surface is clean. Then bolt them up. I cannot express this enough though...NO GASKET BETWEEN THE MANIFOLD AND HEAD MOUNTING SURFACES. Not even any copper sealant..period. You will be asking for problems down the road. Just ask me how I know...besides...Ma Mopar never used gaskets when the cars were new. Must be something there....Good luck/cr8crshr