i have a procharged 350 mag carbed runngin 8 psi. stainless marine headers .30 over full msd ignition billet distributor, and a small cam. i need some suggestions on what spark lugs to run it currently is running a ngk heat range 6 should i go u one more heat range it is carbed with 78 front and 86 rear. i am also having the issue with the 2 center plugs running richer on both sides its has a dual plane stock intake .also the starboard header is a little bit cooler i would say about 20 degrees then the port side when comming out of the tail pipes. i think the sarboard side is getting more water any way to ristrict it. the headers have two inputs and one out put to the riser the front input on both headers had like a spring loaded check valve thing seams like the starboard side has less tension which may allow more water. what shoudl i do with the sring check valve thing. and the rear feed has no check valve on either side.

please any help would be awesome

Your asking alot of different questions on a uncommon combo. In a blower engine you want to run a cooler heat range plug, I think your motor would take a AC MR43 plug as a stock replacement, so look up Autolites web site and cross reference that plug to a heat range 1 or 2 ranges cooler.

As far as your exhaust goes, If your running a stock merc t-stat housing with 4 water dumps, make sure the 2 dumps that have a constant water flow go thru the lower manifolds and the 2 that dump water when the t-stat opens go to the upper risers. I would get rid of the check balls in the system.

Blower motors run hotter and make more heat then a N-A motor. You have to watch everything pretty close so you dont burn anything up. Good Luck.


LE

well thats my question both dump ports go to the bottom of the manifolds and then are pumped out one exit hole on the top the riser and injected in to the riser i will see if i can take a picture of the set up to show what i am talking about. i dont think any of the water goes through the connection point of the manifold and riser but i could be wrong. it is connected together with a v band clamp.

On a blower motor, you want to run a cooler plug. Are you running a BR6FS???? That is a stock plug. If so drop to BR8FS.

yea the br6fs is the plug i am running right now. 2 steps colder ? not just one . also what do you think i should gap the plugs at i have them now at .32 i just want to get this thing up and going again went 70 on 7 cylinders lol but i would like all eight. i think i got the problem with the dead hole bad plug wire. thanks for your help so far

on a carbed supercharged motor I would not be running a stock dual plane intake. The uneven fuel distribution can hole a piston pretty quick.
You would be much better off with something like a single plane edelbrock vic jr for better fuel distribution.

Merc blower engines drop down 2 heat ranges on the plugs to an AC R41T.

The BR6FS is the same as an AC R43T. The BR8FS is teh same as an AC R41T.

You may have to experiment and 2 heat ranges may cause you to foul plugs.

You should be able to gap them at .040 with the MSD.

I am not familar with Stainless Marine exhaust, but like any water cooled exhaust it can only exit thru the risers. The water in the manifold passes thru a transfer tube, or hose to the riser then out the transom. You dont need a separate water supply to the riser. A lot of stock merc and such motors use 4 water dumps on the t-stat system and some aftermarket exhaust systems will accommodate the stock dumps by having 4 water connections on their systems.

LE

Looking at some pictures on Stainless Marines web site, they only have one water inlet on the manifold, the water doesnt go thru the manifold to the riser, but thru the transfer hose between both. Thats how they were designed, you can call Stainless and ask if they recommend removing the checkballs in the t-stat housing to get more water flow.

LE

thanks you guys are awesome. i have been meaning to buy a single plane intake just busy with my new home and my car two many project not enough money. i will try to change out the intake and go two heat ranges cooler and post the results. also going to buy a laser heat gun to check temps.