'74 318 rebuild help?

[killi6]

Hey, everyone...

So I'm rebuilding the 318 on my '74 Satellite. It's got a stock iron intake... is there an oil leak possibility in the intake? There's a sheet of steel attached under the intake that looks like it isn't sealed all around the edges, I wonder if that might be a source for oil that may have caked the combustion chambers with the thick layer of carbon.

Also, I am replacing the cam and was going to go with the stock 340 cam as an upgrade, does anyone know what the stock valve to piston clearance is on these 318s?

In a 'perfect' world, if I have to bore the cylinders and replace the pistons, I'd upgrade to higher compression pistons, but especially with a higher-lift cam, I worry about clearance.

 

[67 B-body]

1. The metal under the intake is a heat shield.
2. It will not cause carbon in the combustion chambers.
3. In 74 you would have TONS of room for valves because it would have been a low compression engine. I would take them out and find 8 good buddies who smoke, and offer them up as realy cool ash trays!
Buy some forged flat top pistons with valve reliefs, have the block "0" decked while it's at the machine shop being bored and cleaned up.
Let the machine shop balance the rotating assy while its all their.
Get a good camshaft, aluminum dual plane intake "Performer", 600cfm carb, break out the die grinder and have at those intake runners, then put it all together.

 

[killi6]

1. The metal under the intake is a heat shield.
2. It will not cause carbon in the combustion chambers.
3. In 74 you would have TONS of room for valves because it would have been a low compression engine. I would take them out and find 8 good buddies who smoke, and offer them up as realy cool ash trays!
Buy some forged flat top pistons with valve reliefs, have the block "0" decked while it's at the machine shop being bored and cleaned up.
Let the machine shop balance the rotating assy while its all their.
Get a good camshaft, aluminum dual plane intake "Performer", 600cfm carb, break out the die grinder and have at those intake runners, then put it all together.

Thanks for the info and the re-affirmation of my plan... (intake and carb upgrade) I'm trying to get it 'driving' for my 40th birthday next May so the intake/carb upgrade will probably not happen by then, but that'll be a 'soon' upgrade, I hope.

If the decks don't have to be ground flat, I thought I'd just get higher-compression pistons rather than grinding the deck. But then, if I can just get stock (or oversized if I have to bore the cylinders) pistons and zero the deck, I already raise compression, and for sure have flat decks to boot, huh?

So many options... having that engine out and on the stand is a huge distraction from the rest of my work...

 

[65affair]

67 b body nailed it... don't forget, you can put in stock compression older year pistons, like from the late 60's. I think the compression was 9-9.5:1 instead of the 8-8.5:1 that you have. And still keep pump gas.
Good luck

 

[killi6]

I'm seeing comments in other forums about intake upgrades... like putting an Edelbrock performer intake and 4bbl on a stock 318 (with stock heads) will make the engine a dog... anyone heard anything on this?

Also, I'm kind of budget-constrained and was wondering if anyone had a recommendation for 4bbl carbs to pick up salvage to put on a performer intake... be nice if I could get a carb for less than $100 rather than a new one for $300.

 

[motorparts92]

The edelbrock performer intake has ports that are sized up for 340/360 heads. Being too big for the 318 heads on a stock motor, it is possible that they could leak vaccuum, or cause flow issues.....true best bet is to get an intake from an 80s dodge truck with a 318 4bbl, and buy one of those remanufactured thermoquads that holley sells......then it will run like God intended.

 

[Secret Chimp]

The edelbrock performer intake has ports that are sized up for 340/360 heads. Being too big for the 318 heads on a stock motor, it is possible that they could leak vaccuum, or cause flow issues.....true best bet is to get an intake from an 80s dodge truck with a 318 4bbl, and buy one of those remanufactured thermoquads that holley sells......then it will run like God intended.

That's only true for one of the Performer intake variants. The most common spread-bore Performer for Mopars has "318/360" cast into it and has the smaller-port runners.

 

[killi6]

Cool, thanks guys!

 

[Dako]

Is your stock iron intake 2bbl or 4bbl? If it's a 4bbl you may want to reconsider swapping it. Do some research on the intakes you are considering. Most aftermarket intakes effect power in the 1,500 - 5,000rpm range. Most stock intakes make their power in the 500 - 3,500rpm range...where most of your street driving is/ will be. Unless you are changing the torque converter to a higher stall and running at the track, you may not see the gains you are hoping for out of an aftermarket intake. Opening up exhaust ports (matching up to gasket openings); installing a mild cam; going to dual exhaust; and, if you can afford it - larger valves(!), will get you a bigger bang for your bucks...even using stock exhaust manifolds. Most owners rarely take their motors much north of 4,000rpm. I would talk with the machine shop you plan to use before buying anything. A good shop will help you map out your engine goals in advance.

Just trying to save you some cash.

Oh, and don't ignore your gearing. Loads of work can be done on a motor, but with original highway gearing (2.94, 2.97, 3.03) you won't see its real capabilities. Running 3.23, 3.55, or 3.73s will proportionally provide noticable improvement in acceleration...'but' (theres always one of those) at the same time make it less user friendly at hwy speeds. Everything has trade-offs.

 

[killi6]

Well, 'Phase 1' of the rebuild is to get the car driving again, Phase 3 is for performance upgrades. Part of Phase 1 though is an engine rebuild so while I'm doing that, I'm doing the bottom end work (340 cam and new higher-compression pistons if I need to bore cylinders, otherwise maybe the decking to raise compression a bit). I plan to leave the top end stock (heads, intake, carb) for Phase 1. Also since I cut up the exhaust pipe when taking the car apart, I'll be putting in new exhaust for Phase 1 which I want to do dual rather than the stock single.

it's a 2BBL intake.

I wasn't planning on swapping heads any time soon... but it sure is fun to read about.

 

[Secret Chimp]

Get a 4 barrel for that cam. My stock 2 barrel was literally running out of air to move past 3800 rpm when I used a Summit 6900. I got a used Performer intake and Carter AVS (625 cfm) and it made a huuuuge difference.

 

[Meep-Meep]

I ran a factory iron 360 intake and the TQ carb on a stock 318 and it ran fine, port mismatch and all. The key is to not kill the engine with too much cam and not enough compression. The factory 340 cam for the 72 / 73 engine is a nice upgrade and the 360 iron intake should be almost free. It's a good piece once you block the EGR. Also plan on freeing up the exhaust.