intake manifold leak

[b-bak73]

hi,im guessing this has been asked before but has anyone had trouble with getting an aluminium intake to seal on the engine?,i have a 383 in my 70 challenger which i rebuilt about 6 months ago,its fitted with a edelbrock dp6b 6pak manifold ,after a couple of hundred miles it started to misfire down the passenger side bank of cylinders,i pulled the plug leads off one at a time to trace it down to a cylinder,but it made no differance,so i guessed i had a vaccume leak and tightend the manifold bolts up some more ,this fixed the problem but i have allways had a lot of back firing when i back off,this makes me think i still have a leak some where.
when i rebuilt the engine i used a petrol resistant loctite sealer around the ports both sides of the steel gasket,i think the sealer stays in a gel state so it may have been sucked into the intake,im thinking about having another go at sealing it down with a different sealer.
another problem i have is when im crusing down the road the car feels as if i have tapped the brakes lightly all of a sudden then comes right then does it again down the road further on,it has boosted discs so im wondering if this has somthing to do with my vaccume leak problems,its weird ive never had anything like this before,at first it freaked me out cos i was thinking my newly rebuilt motor was nipping up on a rod journal!,but ive done 800miles since and its still going,anyone got any thoughts on thease issues?thanks.

[hemiken]

OK........ For starters you should remove the intake and clean all gasket sealant from the tin base gasket.  The best thing for applying a big block Mopar intake on to the heads and gasket is to spray just the area that the intake seals to the gasket with a product called Polamer, it is Blue in color and forms a thin layer for sealing purposes,  if this is not available you can use plain ordinary wheel grease thinly as a sealant.  Do not use any gasket making material or paper gaskets for the intake to seal against the heads.   The same wheel grease can be used on your Carby base gaskets.   Be careful that none of the gasket maker you had on their is blocking any of the orrifices or you will have more problems.   Hope this helps for now.

[b-bak73]

thanks hemiken,i will have a look out for polamer ,i see youre in austrailia ,im in newzealand so theres a good chance they sell it over here,never thought of using grease,thanks for your help.

[hemiken]

Hey No worries ......... i have helped plenty of Kiwis out. Good chance you will have Polamer, not 100% on the spelling but it is in a short can about two thirds the size of VHT engine enamel cans in size.  It is special material used for tin and copper gaskets SOme of my best freinds are Kiwis but dont tell anyone

[b-bak73]

 :biggrin:haha,i wont tell anyone,i lived in perth for a while,im one of the few kiwis who came back home,by the way have you ever delt with that elko performance outfit?

[hemiken]

Yes, i know Elko............. What is it you want too know

[b-bak73]

ive bought a few parts from them,but have given up on them now,great to deal with over the phone,but got tired of ringing them up to find out where my parts were,i was told parts are in stock and being sent out tomorrow,two weeks later no parts,so i get on the phone,'will be sent tomorrow',another two weeks same story etc.
when i first saw their add i thought ,great some one down under selling parts,should save me heaps on freight,but i dont bother with them now.

[hemiken]

Same old run around story as everyone else gets buddy.  Do not think you are special getting the same treatment

I priced some parts today to see if they are in check with their pricing and it seems they are getting a little bit gready for the moment.  Time will tell..............

[Chryco Psycho]

backfiring in the exhaust when off the htrottle is usually a sign of a leak in the exhaust system drawing in air & causing combustion in th e pipes