so i'm rebuilding my original 1970 340

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Money better spent elsewhere than finding lightweight stuff for what it appears the desired performance is. JMO
 
harrisonm said:
Except a stock 340 with 14" tires and 3.55s will not get 22mpg. It's going to take small gears (like 2.94 or less) plus an overdrive transmission to get 22mpg from a 340.
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3.23 gears..and i think mine gets 20 plus mpg driven sensibly, but my cam is stock lift with a little less duration...and that would be an Imperial gallon here in Ontario.
 
Pistons at 0 deck, 72 cc heads.I think around 9.25:1
This will make the racers gasp... but the old generic 204/214 .429/.449
pulls hard from 800 rpm to well past highway speeds
 
204-214 pulls but pulls hard???
It gives up a ton of area under the curve and closes the intake late
what not *** not to like
 
it is one owner 3000 miles since refresh nothing new in engine just gaskets rings hone , other than that bone stock original heavy pistons. I've done it once but engine was stolen , this time I just want the best stock build possible .i know 22 mpg or more is possible as i've done it . last time had stock rods and crank , don' t need or want mega power ,at .the road course all i need is something that will be fun to drive I'm not racing just having fun 3000 to 6500 rpm is where it will run with 3:55 gears and the GV OD .
I'M NOT doing this to impress anybody just a build to see what can be done . besides rather spend the money now than give it away to welfare cheats and refugees when i die
YOU ALL don't have to like it , i'm just having a hard time finding a lightweight crank rods and pistons for a non stroker stock spec build
 
harrisonm said:
Except a stock 340 with 14" tires and 3.55s will not get 22mpg. It's going to take small gears (like 2.94 or less) plus an overdrive transmission to get 22mpg from a 340.
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yes it will I've done it 3:55 and the gv did it
 
Wyrmrider said:
is this a one owner vehicle?
been apart before?
let's do a compression check for a baseline
if rebuilt someone could have put rebuilder pistons it to cut down on the detonation- pinging
you know about octane creep?
carbon build up
If it is an oem early 340 let's figure 9.2-9.7:1 depending on gaskets
too bad KB does not make a quench dome piston for these stock strok stroke 340's
but worth pistons getting custom made
but hard to make one work in a non race motor with stock heads
stroker kit gives you best choices in pistons
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engine is inn good shape had 160- 170 cyl pressure when i put it away , not sure on heads probably go with a set of edelbrock alu or trick flow intake will be an air crap as they worked well on the engine that was stolen
 
273 said:
You get 22 mpg now, how much more can you possible get and what really $$$$ savings would that get you, what do you spend on gas a year now $500, $1000, $2000? even if you could save 10% on $2000 is only $200 a year. If you do a lot of Highway install an OD tranny but I wouldn't neuter the performance too much for a couple more mpg's.
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it's not to save money but to see if it can be done **** i've spent 3000 on gas this summer using vp 110 mixed in with pump gas because of the crap they call gas these days engine would run on when turning it off , might as well piss in the tank gas just sucks
 
Wyrmrider said:
204-214 pulls but pulls hard???
It gives up a ton of area under the curve and closes the intake late
what not *** not to like
Click to expand...

Make no mistake, its by no means a drag car..Let me re phrase that ....pulls hard enough to be fun.
After reading the opps request for power between 3500 - 6500 he is going to need much more cam and will lose low end torque.
He may be disappointed in the street performance.
 
@273
You get 22 mpg now, how much more can you possible get and what really $$$$ savings would that get you, what do you spend on gas a year now $500, $1000, $2000? even if you could save 10% on $2000 is only $200 a year. If you do a lot of Highway install an OD tranny but I wouldn't neuter the performance too much for a couple more mpg's.
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I DID GET 22mp with the engine that was stolen , now getting about 15 mpg with the 426 stroker in the car now getting expensive with 3 gallons of 110 octane with every 10 of piss .i just want something fun to drive , that revs quickly and gets good mpg . don't do much city driving mostly higway and back roads. f I want fast I'll put the stroker back in
this is just a project to see if it can be done and to keep busy. As for cam i think a mild roler with good amount of lift and not much duration should do fine , not impressed with lopey cams want good all around performance with max hp around 6200 - 6400
 
Nat said:
@273
You get 22 mpg now, how much more can you possible get and what really $$$$ savings would that get you, what do you spend on gas a year now $500, $1000, $2000? even if you could save 10% on $2000 is only $200 a year. If you do a lot of Highway install an OD tranny but I wouldn't neuter the performance too much for a couple more mpg's.
Click to expand...
I DID GET 22mp with the engine that was stolen , now getting about 15 mpg with the 426 stroker in the car now getting expensive with 3 gallons of 110 octane with every 10 of piss .i just want something fun to drive , that revs quickly and gets good mpg . don't do much city driving mostly higway and back roads. f I want fast I'll put the stroker back in
this is just a project to see if it can be done and to keep busy. As for cam i think a mild roler with good amount of lift and not much duration should do fine , not impressed with lopey cams want good all around performance with max hp around 6200 - 6400
Click to expand...


If your looking to make peak power around 6200-6400 rpm with a 340 my guess that's about 450 hp. If your trying to build with good mileage and driveablity I do it like how LS and modern hemi's do it lots of head air flow and mild roller cam. Normally most would use 240-260 cfm head with 10.5:1 and a 285 ish cam to reach your power goal, I'd go with at least 280-300+ cfm heads with high rocker ratios to put you in the heads air flow sweet spot and keep the duration relatively small, once you decided on heads I'd play with different cam timings in a dyno program.
 
273 said:
If your looking to make peak power around 6200-6400 rpm with a 340 my guess that's about 450 hp. If your trying to build with good mileage and driveablity I do it like how LS and modern hemi's do it lots of head air flow and mild roller cam. Normally most would use 240-260 cfm head with 10.5:1 and a 285 ish cam to reach your power goal, I'd go with at least 280-300+ cfm heads with high rocker ratios to put you in the heads air flow sweet spot and keep the duration relatively small, once you decided on heads I'd play with different cam timings in a dyno program.
Click to expand...
that is around what i'm thinking small roller lots o lift and decent heads , just want the light crank and rods cause my last 340 had stock **** except for heads , want to see the max that can be made of the 340 , quick not fast and super reliable with better than good mpg
 
Well...this is obviously a 'drooling over the parts catalog' type of question, because the OP doesn't really know what he's asking for, or why.

But fine. Everyone has missed the mark entirely. Scat? Puh-leeze.

Call up Crower or Winberg or one of the other top shelf crankshaft guys and order a 3.31 stroke crank made to your specs....tell them you want it as light as possible. They will make you any stroke you like, none of this 'can't get it BS'. Then, get some SB Chevy titanium con rods. Then, call JE or Diamond or just about any top shelf maker and order a set of pistons with pins....tell them you want them as light as possible, regardless of strength.

Make sure you tell each maker that cost is no object - that will be important. But it's clear that nothing less than the ultimate will do and by God, you shall have it.
 
How much cam can ya run and keep 20ish mpg. That's a long way to look at it

Short way is..i wonder how much mileage I'll get with this small mild solid roller cam....and these custom made light weight ross pistons, these light rods...and this fuel injection setup..implementing quench...this ignition that I can time each cyl independently for max hp..
It's the last thing you find out


I'd be interested to know.
My car w/4spd, 340 ld 340 dual plane cam'd .528 284 112= 17mpg w/o vac advance.
410cid sbm quench motor mild solid roller ,ported j's 186cc int ports , ld340 dual plane cam'd .575 281 108 =15mpg w/o vac advance.

20-22 mpg isn't far out.
 
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