MOPAROFFICIAL
If it has tits, it's a liabilititty.
So I put my 340 back in the car , 8 yrs later, after losing a cylinder wall in my 410 ar the track..
The thing I changed with this version is the heads. It used to run like 13.5- 13.8 @104 on street tires with a 4-speed at the track, yes 1/4.
That motor had lost a push rod ball or three and the cam was hurt, so that's why it came out for the 410.
I went through that motor, changed all the bearings n took the block down and had it touched with a hone for the fresh moly rings.
I put the X heads on the bench with the 3/8 stem Mancini stainless valves I had in them and they were only moving about 218 to 221 cfm with one doing 242...'long story on that'.. so I put them in the shop for a light Mill and 11/32 guides. They were actually to be fully built with the valves I supplied, but when I got the heads back and went to do some Port work on them.. I found that the shop screwed me. All of the intake valves we're riding at the very top near the satellite of the valves, seats were way too small. I no longer use that shop. So I did the valve job myself and ported them..then upgraded the springs to pioneer 'sold by engle at the time' doubles 150/340. On the bench they flow 271 to 278 CFM and im happy with that... somewhere along the lines I decided to change the valves out for better valves, going from Elgin Pro stock stainless to engine Pro perf stainle$$ and their nitro black exhaust valve$.
I had an extra 528 solid laying around, used but in great condition, and so I purchased some 821 comp solid lifters and tossed it all in.
Cam is in @ 105, about 7 degrees advance which is where it runs best ime...'I've ran 3 from straight up, 2 degrees adv and 5 adv ..'
The motor is around 9.7ish compression , has an port matched LD340 w/ 3/8 spacer w/750 demon dbl pmp and tti's through 3" pipes/ultraflo muffs
Atm its jetted 74/83 w/31 squirters and 8.5 pv , idles around 10" vac timing is around 24/32 all in @2200
Last time, old heads, same everything else except the headers were 15/8 and 2.5 pipes.. it liked 73 jets. This carb ootb is 76/83
Its getting real close to where it wants to be. Thinking 75 jets and maybe 26/34 timing, maybe.. and I might try higher rated power valve and see if I can get this idle ease to work. I have stuck a wrench down in there and have not yet gotten that thing to move. It is closed and seized it seems.
The thing I changed with this version is the heads. It used to run like 13.5- 13.8 @104 on street tires with a 4-speed at the track, yes 1/4.
That motor had lost a push rod ball or three and the cam was hurt, so that's why it came out for the 410.
I went through that motor, changed all the bearings n took the block down and had it touched with a hone for the fresh moly rings.
I put the X heads on the bench with the 3/8 stem Mancini stainless valves I had in them and they were only moving about 218 to 221 cfm with one doing 242...'long story on that'.. so I put them in the shop for a light Mill and 11/32 guides. They were actually to be fully built with the valves I supplied, but when I got the heads back and went to do some Port work on them.. I found that the shop screwed me. All of the intake valves we're riding at the very top near the satellite of the valves, seats were way too small. I no longer use that shop. So I did the valve job myself and ported them..then upgraded the springs to pioneer 'sold by engle at the time' doubles 150/340. On the bench they flow 271 to 278 CFM and im happy with that... somewhere along the lines I decided to change the valves out for better valves, going from Elgin Pro stock stainless to engine Pro perf stainle$$ and their nitro black exhaust valve$.
I had an extra 528 solid laying around, used but in great condition, and so I purchased some 821 comp solid lifters and tossed it all in.
Cam is in @ 105, about 7 degrees advance which is where it runs best ime...'I've ran 3 from straight up, 2 degrees adv and 5 adv ..'
The motor is around 9.7ish compression , has an port matched LD340 w/ 3/8 spacer w/750 demon dbl pmp and tti's through 3" pipes/ultraflo muffs
Atm its jetted 74/83 w/31 squirters and 8.5 pv , idles around 10" vac timing is around 24/32 all in @2200
Last time, old heads, same everything else except the headers were 15/8 and 2.5 pipes.. it liked 73 jets. This carb ootb is 76/83
Its getting real close to where it wants to be. Thinking 75 jets and maybe 26/34 timing, maybe.. and I might try higher rated power valve and see if I can get this idle ease to work. I have stuck a wrench down in there and have not yet gotten that thing to move. It is closed and seized it seems.
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