Moparchat - Home of MOPAR enthusiasts worldwide!



Go Back   Moparchat - Home of MOPAR enthusiasts worldwide! > Technical Forums > Performance Talk

Click here to search for Mopar cars and parts for sale.


Reply
 
Thread Tools Display Modes
  #1  
Old 10-29-2001, 11:32 AM
cushmanr cushmanr is offline
Inactive User
 
Join Date: Oct 2001
Location: Orono, Maine
Age: 45
Posts: 12
Question optimizing my 318

I had my 318 rebuilt a couple of years ago, it now has 14k on it. It was bored .030" over and I had a replica of the mopar muscle cam put in it (.429/.444). The pistons are 8.5:1 flat tops. I am currently in the process of getting things together to put a mopar purple shaft in it (.430/.450 lift). I am also getting mopar adjustable pushrods and am considering shaving my heads .030" and using a .030" head gasket. The heads are stock and have not been touched. I was also going to port and polish. I was also going to put in the mopar performance distributer with adj vac advance.

Will these modifications to the heads be fine with piston to valve clearence, or can I do more or should I do less? I am trying to get some more compression out of the motor. Currently I am getting between 130 and 140 cranking pressure in each cylinder. I have got a 600 Holley with an Edelbrock Performer Intake to feed it.

Is there anything else that I should consider in doing these modifications or tips on what I could do along these lines.
Reply With Quote
  #2  
Old 10-29-2001, 12:27 PM
Plum Crazy Chris Plum Crazy Chris is offline
Inactive User
 
Join Date: Nov 2000
Location: Austin, TX
Posts: 94
Default

Ryan, If your doing to go through the trouble of working your heads a little, check out some new ones.

Aero Racing has remanned 318 heads with new hardware, a 3 angle valve job and bigger valves, (1.88 and 1.60). All for $399 a pair.

You could keep your car on the road, get the new heads, have them shaved if neccessary, and then swap heads and cam in the same weekend.

I assume you already have headers on it. If not, consider adding them first.

Good luck and let us know what you decide.
Reply With Quote
  #3  
Old 10-29-2001, 02:35 PM
rumblefish360's Avatar
rumblefish360 rumblefish360 is offline
Moparchat Bronze member
 
Join Date: May 2000
Location: C
Age: 57
Posts: 11,120
Default

When your lift gets to about .600, you might hit then. Unless you install the cam half a$$ed. The lift increase you have there is nothing. Just install the cam and DEGREE IT IN.
Do some math on the compression to make sure of where you are and where your going. A half point increase is good. 1 point is the limit on your mello street machine there. At 9.5-1 good gas is required.
Double check the clearance in piston to valve clearance when you star getting it together. Then you'll know for sure. And thats what you want, to know for sure. I bet there be a ton of room.
The new head idea is a great one. You'll still be driveing around while the build up is going on. Have all the porting work done before final assembly.
Headers are a real big plus with that combo. They will help unleash the power. Go duals with a "H" pipe (MIN., or "X") with the pipes out to the rear bummper.
The 4bbl intake and carb you have is very good for what you have. Add an MSD, and open air cleaner. Just remember the little things and it'll sing nice for you.
Reply With Quote
  #4  
Old 10-29-2001, 09:06 PM
cushmanr cushmanr is offline
Inactive User
 
Join Date: Oct 2001
Location: Orono, Maine
Age: 45
Posts: 12
Cool

Thanks for the replies. I will look into the Aero heads. I am currently running headers with a K&N open air filter, however I haven't got an H-pipe in though. The reason for the cam change is that the cam that I have in it is a cheap replica (wolverine) and I have a lot of lifter noise. Looking through the Mopar A Engines catalog it suggests that the .430/.450 lift is a much better choice over the 340 cam. I am assuming because it is on a smaller centerline. I will check the head option out though. Thanks again.
Reply With Quote
  #5  
Old 10-30-2001, 12:10 PM
Plum Crazy Chris Plum Crazy Chris is offline
Inactive User
 
Join Date: Nov 2000
Location: Austin, TX
Posts: 94
Default lifter noise....?

If you have lifter noise, you might just need new valve springs. That happened to me before, I had gotten new ported bare X-heads for my 340, but didn't drop the dime for new valve train, just swapped out the stuff from the 318 I was replacing. Those springs just couldn't handle the lift and it sounded terrible, like it wasn't getting oil or something. Stiffer springs and viola, smooth revs, no clatter.

Its a lot cheaper, but I would still go for the aero heads, its the best cheapest performance swap you can do. Do a little porting/gasketmatching and you should really feel the difference.

Good luck and take your time.
Reply With Quote
  #6  
Old 10-30-2001, 02:42 PM
cushmanr cushmanr is offline
Inactive User
 
Join Date: Oct 2001
Location: Orono, Maine
Age: 45
Posts: 12
Thumbs up valve springs

That probably is what is wrong. I still have the stock springs in the motor. According to documentation the stock springs will only hold up to a little over .400 lift. I will try to find some information on aero heads and may go that route. With the aero heads, are the valve springs good ones or are the heads mostly stock with bigger valves? I will try to find out. Thanks for the info.
Reply With Quote
  #7  
Old 10-31-2001, 01:19 PM
Loghead Loghead is offline
Inactive User
 
Join Date: Oct 2001
Location: North Scituate/RI
Posts: 104
Default

Cushmanr,
$399/pair for heads, what a deal! Those heads would really wake that 318 up, even without the new cam( I would put the new cam in while it's apart though) Like someone already requested, let us know how it works out.
Reply With Quote
  #8  
Old 10-31-2001, 03:21 PM
Frans Veldman's Avatar
Frans Veldman Frans Veldman is offline
Inactive User
 
Join Date: Apr 2001
Location: Netherlands
Age: 59
Posts: 59
Default

Can anyone tell me who sells these aero heads for the 318? Do they have a website?

Thanks,
Frans Veldman
Reply With Quote
  #9  
Old 10-31-2001, 05:03 PM
goldduster goldduster is offline
Inactive User
 
Join Date: Dec 1999
Location: Corry, PA
Posts: 535
Default

I wouldn't use mopar's purple shaft cam. Personally, I'd use a Comp Extreme Energy 262 or 268. its a way more modern cam grind, and has worked extremely well in Mopar Muscle's recent buildups of 318's, 340's and 360's.

The Aeroheads are sold by Aerohead Racing Components. Here is their contact information:

Aerohead Racing Components
8621 Southeastern Avenue
Indianapolis, IN 46239

Phone: (317) 862-0224
Fax: (317) 862-6300

That is from their ad in Mopar Muscle Magazine.
Reply With Quote
  #10  
Old 11-07-2001, 02:28 PM
Karl43 Karl43 is offline
Inactive User
 
Join Date: May 2001
Location: Detroit, MI
Posts: 215
Default

Your cam choice is a little conservative for your heads. I run the same MP cam 260-268-44 .430-.450 in a 318 with 77 360 truck heads ported and opened up to 2.02. When you port the heads want to flow at higher RPM. Try one more step up for the cam the MP 268-272-50 .450-.455 cam. It will have a little more top end for your ported heads. That is the cam I have for my next 318 four barrel.

The first cam is better than the stock 340 as it has the same overlap, less intake and exhaust duration (lower rpm band) and has .001" more intake lift and .006 more exhaust lift than the stock 340 cam. Therefore it is a nicer milder street cam. If you go with the 268-272-50 cam you have about the same duration as the stock 340 (4° less exhaust only same intake). A little more overlap, and more lift. It has .450-.455 compared to the 340 cam at .429-.444. I recommend running the 268-272 cam with variable duration Rhoades lifters to keep the low end and mid range without sacrificing top end. Even with the 260-268 .430-.450 cam it has nice pull from low end to top end. But one more step up in cam would be nicer
Reply With Quote
  #11  
Old 11-07-2001, 09:22 PM
cushmanr cushmanr is offline
Inactive User
 
Join Date: Oct 2001
Location: Orono, Maine
Age: 45
Posts: 12
Default Thanks

Thanks for the advice. I will think about that in the future. For right now, I already have the cam. If I was running a little more compression and different heads, like the ones with the 2.02 valves, I would probably put that cam in it for sure.
Reply With Quote
  #12  
Old 11-09-2001, 11:46 AM
cushmanr cushmanr is offline
Inactive User
 
Join Date: Oct 2001
Location: Orono, Maine
Age: 45
Posts: 12
Thumbs up Aero heads

Well, I descided to go with the heads. By the time that I put new valve springs on the original ones and put new guides in, I might as well get the reman heads. This will be alot better anyway, because the truck won't be setting in a cold garage with the heads off it for 2 or 3 weeks.

Thanks for the idea on the heads Plum Crazy Chris, I would have never known about them. I will let you know how it turns out. I am putting a G-Tech in it this weekend to see what I have with the setup now. When I get the new cam and heads on, I will let you know how much difference it made.

Thanks again,
Ryan
Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
optimizing my driveline fastback340 Drag Racing Forum 6 01-26-2002 11:32 AM




All times are GMT -4. The time now is 06:51 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
. . . . .