340 Build advice needed!

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Moto2005

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I currently have a 340 block 60 over and standard 3.31 stroke with j heads, I tore it down and the cylinders look brand new with the cross hatch still in them and normal pistons, i'd like to not touch the bottom end if at all possible. What i need advice on is choosing a cam or cam kit, I was looking at a comp cam complete package with cam lifters springs and timing chain set, what would be my best cam option for a streetable 4-speed duster. I also plan on using a Torker 340 intake and a holley 650 dp possibly headers and mild port work
 
i was doing some research, id like to go roller but on a budget also i found comp cams PART #20-742-9 cam, and doug herbert solid drop in roller lifters, any input would be appreciated
 
well that solves the roller lifters now i just need to make a cam selection
 
Moto2005 said:
well that solves the roller lifters now i just need to make a cam selection
Click to expand...

Do you know what your compression will be?
You do realize that solid roller springs are fairly expensive?
Comp's 917 springs will work well, but you'll need harland sharp rockers to clear the springs and handle the spring pressure.
Plus the pushrods need to be fairly stout, no 5/16 .080 wall IMO.
Just want you to think about the things you'll need and their cost.
Brian
 
compression should be a little over 10.5, I am aware of the new springs and i want to go roller rocker anyway, when i buy the new parts i figure im doing it one time, so i mine as well go with the good stuff so i dont have to yank the motor again
 
I am aware of the cost, the compression will be a little over 10.5:1, i just want to do it right the first time, are Harland sharps the only option for rockers? I wanna keep this cheap but still a stout street motor i just thought roller would be a great way to unleash some of the small block power without rebuilding the entire bottom end since it was recently done
 
Moto2005 said:
I am aware of the cost, the compression will be a little over 10.5:1, i just want to do it right the first time, are Harland sharps the only option for rockers? I wanna keep this cheap but still a stout street motor i just thought roller would be a great way to unleash some of the small block power without rebuilding the entire bottom end since it was recently done
Click to expand...

I think TD might clear...maybe. I wouldn't use anything else because they won't hold up as well and may not clear those springs.
HS will clear I'm sure.
 
Brian, those Harland Sharps clear the MoPar springs?
What other ones do?
 
any other helpful hints? i'm thinking about porting the jheads myself and a valve job as well, but im still undecided on a cam
 
thats the other problem, i havent identified the pistons in the block yet, the previous owner was not the builder so i'm kinda stuck right now, im going to try and identify the cam in the motor tonight to see what the previous lift was that im working with
 
what about a solid flat tappet like the comp xs-282s it's .520/.540 lift and good duration for a hot street motor. Heads can surely make a world of difference and there's some great threads on here about porting you can read up on.
 
i dunno, im torn between solid roller or hyd flat, maybe ill just get a nasty hyd roller and regasket the motor as it is and save up for a buil next year, grrr decisions decisions
 
Take a picture of the pistons at the top of their travel and post it... I need to see what "normal" is before I would give any cam choices...
 
cant give much more advice than what you already have got, but i think that cam your looking at is a pretty powerfull piece, i have a comp extreme energy roller, the next size bigger than the one you are looking at and it has a very nice midrange and topend, alitle bit rough at idle but as soon as it starts making power it realy ran nice, its a few years since it ran but i miss it everyday, very streetable as long as you have alitle more converter than stock
 
wow, solid roller lifters are cheap these days
http://www.dougherbert.com/rollerlifters-p-10099.html?cPath=83_93_683

throw a MP solid .590 in it.lol

pic of pistons is needed, or part#.

what do the heads flow?

nasty? narrow cl,more o lap

from the 1st post..I wanna just tell you to put a .509 in it.
how anyone could be stuck between a solid roller and a flat tap hyd is a mystery to me, or a case of 'here comes a million questions'-a guy that does not know what he wants.

good luck.

ps. the mp .528 & .557 solid flat tappet cams run hard in mildly ported head 340's
 
ok piston part #L2136 .030 for 30 over, I looked over the heads again tonight, there gonna need hardened seats put in and the last person that did it has larger springs that stick out past the retainers and shimmed, its pretty hacked, so im starting with the heads and workin my way down from there, im keeping the heads pretty much factory i might port them a little
 
Assuming the block was decked as was typical and the heads were done the same way I'd say your static compression is no higher than 9.5:1. Lower is you have aftermarket (Felpro, Victor,etc) head gaskets. So I'll give two ideas. First... Roller cams are out. Overall its the cash and you're current setup simply don't make sense to me to spend that cash. So if you are having the heads worked a little I'd go with the SK20-220-4 (XE274H kit) because it requires double valve springs and your heads may need the seats and guides cut for that. If you aren't doing anything to the heads, I'd go down one to the SK20-223-3 (XE268H) because it can use single springs which will drop on the heads.
 
well.... bad but good news, we got the bottom end apart today, looks like ill be needing a crank and rods as well, someone welded on the crank and tried to do a home balance job, in the process 2 rods had bushings installed or something similar to that....looks like ill be going stroker!!!! any input is appreciated
 
Ditch the Torker 340 and go with an Edelbrock Performer RPM or the RPM Air Gap.
The Torker is 1970s technology and is better suited for the track than the street.
You'll be much happier with the Performer RPM or the Air Gap.
 
ok, here it is, standard stroke mopar forged crank, eagle rods, forged trw float pin flat top pistons 30 over, i have j-heads mild porting with fresh valve job, so basically a stock 340, im planning on getting headers and using a holly 650 dp, the car i have is a 4-speed and i want to run 3.73 gears, a good streetable motor with plenty of power that ocasionally may hit the strip......what i need to know is what intake and what cam to go with, ive been all over the place trying to decide, but since the bottom end needed work ive been looking at the comp cam complete kits since i need all of the components anyway (springs, retainers, locks, timing setup, cam and lifters)...........opinions or advice???? thanks
 
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