Joe Darte
Member
Throwout bearing on my 340LA / A833 OD was trashed, so I used the opportunity to pull the engine and trans for a good cleaning, re-sealing, repainting, and some fresh dress up.... well that got WAY OUT OF CONTROL.
The engine supposedly had 5,000 miles on it when I bought the car. I wanted to do some oil system upgrades. When I had the pan off, the cylinders looked brand new. The 1967 Dart it belongs in has always impressed everyone on the butt-Dyno. I knew it wasn’t stock, had a hefty cam, possibly some porting, obvious bolt ons. So I decided to lift the heads to really find out what I had.
So let’s get down to the meat of it and get to my questions. I’ll supply as much information as I possibly can.
The old running set up is as follows.
1972 340 block, bored 0.030” over for 4.070 bore.
Stock cast crank, 3.31” stroke.
Stock rods.
Mildly (although amateur appearing even though done by a “porting service “) ported 915 J-heads with 2.02 / 1.60 valves, unknown springs, and what looks like aluminum retainers (non magnetic, can scrape them with my knife) so doesn’t seem like titanium to me. Unknown if the heads were milled. Stock stamped steel rockers.
Pistons are cast, they come up 0.1045” shy of the deck. They have 4 valve reliefs cut in the flat top.
Double roller timing chain.
The cam is also a mystery. It sounds mean at idle. The car has no issues idling at 650rpm and has a choppy sound. I’m guessing 108ish degrees of LSA. The only measurements I could pull were .270/.299 lift on the lobes.
Headman headers, Edelbrock Performer RPM intake, 1407 750CFM.
Looking to squeeze a little more power with just bolt-ons. I’m looking to get Edelbrock 6077 heads with 63cc combustion chambers to bump the compression a little, and some better flow. But I was also looking at a set of 1.6 ratio full roller rockers. Do you guys think 1.6 rockers would be safe to run with what appears to be stock cam timing? I didn’t see any means of degreeing the cam, looked like a standard double roller timing gear. Or am I crazy for thinking about increasing the valve lift without knowing my piston to valve clearance on my current set up? We are only talking about 0.027” - 0.030” more valve lift with 1.6 ratio rockers.
The second photo is the engine currently. I was just about finished with the engine except for the rockers. That’s when I started toying with the idea of buying the compression with the 63cc heads and putting a higher quality rocker in it.
The engine supposedly had 5,000 miles on it when I bought the car. I wanted to do some oil system upgrades. When I had the pan off, the cylinders looked brand new. The 1967 Dart it belongs in has always impressed everyone on the butt-Dyno. I knew it wasn’t stock, had a hefty cam, possibly some porting, obvious bolt ons. So I decided to lift the heads to really find out what I had.
So let’s get down to the meat of it and get to my questions. I’ll supply as much information as I possibly can.
The old running set up is as follows.
1972 340 block, bored 0.030” over for 4.070 bore.
Stock cast crank, 3.31” stroke.
Stock rods.
Mildly (although amateur appearing even though done by a “porting service “) ported 915 J-heads with 2.02 / 1.60 valves, unknown springs, and what looks like aluminum retainers (non magnetic, can scrape them with my knife) so doesn’t seem like titanium to me. Unknown if the heads were milled. Stock stamped steel rockers.
Pistons are cast, they come up 0.1045” shy of the deck. They have 4 valve reliefs cut in the flat top.
Double roller timing chain.
The cam is also a mystery. It sounds mean at idle. The car has no issues idling at 650rpm and has a choppy sound. I’m guessing 108ish degrees of LSA. The only measurements I could pull were .270/.299 lift on the lobes.
Headman headers, Edelbrock Performer RPM intake, 1407 750CFM.
Looking to squeeze a little more power with just bolt-ons. I’m looking to get Edelbrock 6077 heads with 63cc combustion chambers to bump the compression a little, and some better flow. But I was also looking at a set of 1.6 ratio full roller rockers. Do you guys think 1.6 rockers would be safe to run with what appears to be stock cam timing? I didn’t see any means of degreeing the cam, looked like a standard double roller timing gear. Or am I crazy for thinking about increasing the valve lift without knowing my piston to valve clearance on my current set up? We are only talking about 0.027” - 0.030” more valve lift with 1.6 ratio rockers.
The second photo is the engine currently. I was just about finished with the engine except for the rockers. That’s when I started toying with the idea of buying the compression with the 63cc heads and putting a higher quality rocker in it.
