1 Bad Mirada

i honestly have no idea. i could estimate and say that a 70 340 4bbl was around 275 hp, but i do not have the correct 10.4 to 1 pistons, or the "good heads"...

for the record, my "dyno numbers" are from a computer dyno, but ive talked to a few people who have been to alot of dyno events, and 360-370 at the wheels should be about right for my car/numbers, and with a 20-23% drivetrain loss, the 463 would be correct. ill try to find the site...

RLSH700

Did you build this engine from scratch or did someone do some of this stuff before you got it? Why don't you have the 10.4 to 1 pistons or the "good heads?"

71CHALLENGER

HELLO MIRADA, YOU MENTIONED YESTERDAY ON MY 340 FLAT TOP
PISTONS COULD HURT A LITTLE ON HP.
I THINK I HAVE THE TYPE THAT HAVE THE 1/8' OR SO CUP STYLE DONT REMBER FOR SURE ITS BEEN AWILE SINCE I SHORT BLCKED IT OUT. ON STAND NOW AND RAPPED IN PLASTIC ALSO WILL HAVE TO FIND MY INVOICE TOP SEE EXACTLY WHAT I PUT
IN IT. YOU MENTIONED MILLING THE HEADS SOME????HOW MANY THOSANDS DO YOU RECOMMEND?????
WHAT ABOUT GSKT TYPE AND THICKNESS????/
I RAN INTO A GUY AT ROCK FALLS RACEWAY IN WISCONSIN A COUPLE YEARS BACK AND HE DID THIS
AND ACTUALLY LOSS ALOT OF POWER IN HIS 340..
WERE BRACKET RACING AT THE TIME WITH MY BUDDY AND HIS 440 70 DUSTER.WERE INTO IT QUITE
HEAVY UNTIL HE GOT MARRIED[:@][:@]/OH WELL LIFE GOS ON.
ANY SUGGESTIONS??????????/
OH I WILL SEE IF I CAN GET THE PT#PISTONS AND POST SOME MORE

71 CHALLY MOPAR FANATIC

1 Bad Mirada

my dad is a dodge mechanic who has spent lots of time around muscle cars, and he put the motor together. when i bought the engine when i was 16, it didnt come with pistons or heads. J or X heads go for a premium now, and the higher the compression the piston, the better quality/brand the piston, and the higher the price. at 16, i simply couldnt afford to shell out big money for J or X heads and good pistons...so we bought the cheapest pistons and rings that we could find. my dad didnt want me to get into street racing like he did, so he put the motor together to not run all that great, but once i proved to be responsible with it, the real build began. its nice, because i can run 87 octane, and it still runs well. my engine runs as well as it does because my dad is smart with the engines, and i try to pick up things from him. without him, i would probably drive a yugo or something...

71 chally, the problem with cutting the heads is that you then have to cut the manifold, or it wont line up. also, depending on the type of pistons, the size of the cam, and valve to piston clearance that you have, the amount that you can safely chop off the heads changes. before we chopped my heads, we consulted a friend who works in an engine shop, and he told us what he felt that we could safely chop. alot of math involved...

for head gaskets, we are running the thinnest copper gaskets that we could find..i think that they were from MP, but its been a while.

here is how low the compression on my engine was with the old, unchut heads. at the time, i was running high 13s. we were working on the car at the shop, hurrying to get it ready for an event, and one of my dad's buddies was "helping"...

he took the air cleaner off, and told us that he dropped the wing nut under the car somewhere...when we couldnt find it, he told us that he knows that he heard it hit the suspension, it must be caught up under the car somewhere. well, once the work that we were doing was complete, we fired it up to load it onto the trailer. he had started the engine, and it ran just fine,and had pulled it out of the bay when a different (more competitant) friend told him that something didnt sound right. with it running, he got out and listened, and quickly shut it off...we tore the engine apart and we found the wing nut...in the number 1 cylinder. it was sitting on top of the piston, and the compression was so low that in the few minutes that it ran, it didnt even crush the wing nut flat! it didnt damage the valves or the piston, and it barely scratched the top of the piston. now, that was with the old heads, and the new ones are cut, but i dont recall how much.

71CHALLENGER

HELLO AGAIN MIRADA,
YEAH I KNOW ABOUT THE VALVE LASH AND SUCH, THE DISTANCES ETC.YOUR RIGHT IT IS ALOT OF MATH.
MY BUDDY IS A MACHINIST BY TRADE SO I GUESS WHEN IM READY TO DO THIS I WILL
CONSULT HIM. I APRECIATE ALL YOUR IMPUT ON THE SUBJECT SO FAR TERMENDESLY.
I TKINK WHAT I'LL DO IS PUT IT TO STOCK TO BEGIN WITH AND SEE WHERE IM AT WITH IT.
TEARING DOWN A TOP END IS NOT THAT TOUGH TO DO ANYWAY AND CAN ALWAYS DO IT AFTER
IF I WANT MORE POWER. NEVER HAD A SMALL BLOCK BEFORE, ALWAYS HAD BIG BLOCKS
SO TRYING TO GET A LITTLE IMPUT FROM YOU GUYS ON THE SMALL BLOCK.

POSTING TO SEE WHATS WORKING FOR THE REST OF YOU'S

AGAIN,
THANKS

71 CHALLY

RLSH700

Interesting story about you and your dad building your 340. My uncle is rebuilding a Dodge Royal with the original 241 HEMI small block. The interesting part is he claims the racing pistons cost about the same as the normal pistons, so he is going to put in the racing pistons anyways. My uncle hasn't work for any automotive manufacture, he just does this as a hobbie and he is really good at it too.

1 Bad Mirada

you have to understand that as pistons go, you have performance brands like JE, then you have "performance" companies like speed pro. for a 30 over chevy 350, you can get a "performance piston" from speed pro with a CR of "about 10 to 1" for 12 bucks. so you could get a set for 96 bucks. now, from JE, a set of "performance" 30 over chevy 350 pistons with a CR ranging from 11.4 to 9.4 depending on the combustion chamber size, is 608 bucks...

now mind you, stuff for a SB chevy is a dime a dozen, and stuff for mopar small blocks cost mopar, presumably because they have to use better stuff to stand up to the power...

RLSH700

Naturally, the 350 is used more widely than any Chrysler small-block (espically the original HEMI small-block). You will find 350s in Fords, AMCs, and even Chrysler, but finding a Chrysler small-block in a GM is more rare. This is why it is easier to find 350 parts cheaper.

1 Bad Mirada

they just put it in so many vehicles, and didnt change it for SO long...

RLSH700

That too. The Chrysler small-block was no longer used in cars after the M-body. Their truck sales were very weak until 94. They have had fewer SUVs that used them. They didn't use the small-block in any sports for years. All this time GM keep using their small-block in their car line in both the Caprice/Impala SS, the F-body twins, in their many SUVs, in the Corvette, and their much higher sales than Dodge in trucks. These sales were also higher than Fords so that explains why there were so many of them.