well i scrapped the idea of putting my gs400 in my 65.(convert,lap belt only,not 18 anymore):eek2: i want to "massage"my 340 a bit.what carbs,cams are proven performers.i see poston has reserected the 300-340 headers,but for $300,i think i will keep the stock exhaust and spend the money on port matching,as the stock looks very efficient as is.i am running the stock turbo 300,what about a stall converter?dont want a all-out street racer(thats what the 400 is for)but wouldnt mind kickin some 5.0L ford butt once in a while:Brow: dont want to punch it out to 350 specs either:boring:
340 performance There is aguy on this board that has a 300 with 298 rear wheel horse power he is using the 64 aluminum heads and intake a poston cam and has gasket matched the ports. I know that you can't use the heads and intake but the cam and port work would be of some benifit. Oh buy the way he made that number without headers. A good ignition such as an MSD a good exhaust and carberator will also help to. Another thing that he did that is very simple and he made big gains with was an exhaust X-pipe. I believe he picked up 9 rear wheel horse power when he installed that on a 2.5 inch exhaust with flowmaster two chamber mufflers. He is running i think 11.5:1 compression ratio which is to high to run on pump gas with your iron heads. I believe i read some were that bigger values can be installed in the 340 heads maybe someone can confirm this. With the 4 barrel i believe the 340 made 260 horses and with the above modifications including the exhaust ignition and cam i could see probally 280 horse power. Another thing you could do is run a 2004r tranny which has a lower first gear than your current power glide plus over drive this tranny would make better use of the power you got. thanks Adam
When I rebuilt my 340, I went with stock compression (10.25 to 1?) and used the only cam that was available (ten years ago) which was a Crane. I think the exact cam is still available, and I don't know if anyone else even makes any. Otherwise it was all stock, and even with the stock st-300 the car was quick. Flash forward to now. I added an Edelbrock performer 1406 600cfm electric choke carb. - and you MUST use a carb spacer/heat shield kit to let the linkage clear the manifold - you know, those kits where you have a stack of thin metal spacers and gasket spacers that you stack on top of each other to get the right height between the intake and the carb. This made a huge difference over the stock tired carb. THEN, even better, I added a complete new GM HEI setup. You have to grind a little on the front corner of the intake manifold, but don't let anyone here scare you away from that, it takes just a few minutes and doesn't hurt anything, and you get just enough room to get the right advance. Hello, instant starts, great idle, and power above 4500 rpm. Finally, you gotta get a good dual exhaust setup. With the crossover pipe. Don't go huge, either, like 3", keep it at about 2.5. These mod's really, really woke up my 340 and pretty much transformed the car. Keeps pulling strong right up to shift points, where before it was 'done'... very cool. Next up will be head porting. I'd like to know about the larger valves in the 340 heads too... anyone? Bueller? :beer
ok!! thanks pete,thats what i wanted to hear.poston lists 3 different cams.ignitionman dave is going to get the distributor to convert over.dont like the idea of carb spacer though????have 2 1/4 exaust allready.hope i can just add the crossover & not have to buy a whole new system.:ball:
If your interested Crower makes a few cams, I will list some of them for you. grind adv.dur adv. dur. lift lift ctr lobe intake exhaust intake exhaust #1 Hyd, 112* 250* 258* .424 .430 #2 Hyd, 112* 260* 266* 446 .451 #3 Hyd, 112* 276* 281* .488 .490 #4 Hyd, 112* 284* 290* .512 .526 #3 Sld, 108* 292* 298* .502 .514 #4 Sld, 108* 304* 310* .536 .539 In case, The "Hyd" is for hydaulic lifter, "Sld" is for solid lifter. The name of these cams are Crower Compu-pro camshafts. I bought mine from PAW in California they are priced good to.
Great to see something is out there for these 340's, thanks for all the info....how bout headers?...any ideas?
Yeah intakes would be nice, We need to convince some one to make them.:blast: :blast: :blast: Now get work and you hear a whip cracking in the back round. Josh
