Shortblock help

-
340sixpack

340sixpack

Well-Known Member
Joined
Dec 30, 2007
Messages
624
Reaction score
5
Location
Perry,Ia
Engines out and apart,thinking of doing something new.Currently

340 .040 over
318 steel crank
stock polished rods
speed pro flat tops at deck
j heads 2.02 1.80 63c.c ported flow 270 @.500 lift
comp cam .477 intake .470 exhuast solid lift,duration 246 at .050 108 centerline
and the six pack

Looking at a stroker,problem i have is in the heads now that i will need a larger cam,they go into reversion at .510 lift.

Talking w/Hughes he recommends this
http://www.hughesengines.com/Index/products.php?browse=search&search=5256&partid=21803
or hydraulic:
http://www.hughesengines.com/Index/products.php?browse=search&search=3742&partid=21857

Now my question is will this work?I know strokers require more cam but i
dont want to get into reversion problems.What happens with a smaller cam
combo like a .508?Or another combination?If not a stroker would you change
anything with the current combo?Lots of knowledge here,lets here your guys
opinions.Thanks!
 
That cam your running now is pretty small,i'd go with something bigger..the one that Hughes suggest.. will your heads support it??..as far as the stroker route you really don't need a huge cam to make power,when i first put my 416 together i ran a .494/.513 cam,and the car went a best 11.29..for you i'd suggest just going with a bigger cam,i've had VERY good luck with the Lunati voodoo series..the cam already mentioned,and i also ran the .533/.552 cam in my stroker..going 11.0's...then i built my current 360 with the .513/.533 cam and have gone in the 11.70's with it..your combo looks pretty good more cam would deffinately be the route i would go..
 
I find it hard to believe that heads that flow 270 at .500 will start reversion .010 later. Something sounds fishy. 270 is quite a lot for a smallblodk head. It would have to almost be a fully ported head. a fully ported head should be ok past .600 lift. I'd contact the head porter and see whats up.
 
Thanks stroked 340 thats what i was looking for,a good run down of some numbers.I was not for sure on this cam deal w/a stroker motor,if a smaller
one would lay it down.

Dusterdon,the heads are completely ported,actually over ported at one time.This is where the reversion started.My machinest filled the intake
floors with epoxy to get the velocity back and getting the flow numbers up.I
would of thought this would have fixed the problem,not sure why they are doing this.:dontknow:
 
If i stroke this thing,whats involved?Block modifications,stock windage tray,
oil pan?Drawbacks?
 
I don't think you would have to really touch the block anymore. There is a lot of kits that say theres no clearancing issues and others require some stuff to be grinded. Kinda depends I suppose. For a stroker, I'd look at oiling and cooling. Deeper oilpan, high flow oil pump, bigger/better radiators are a good idea. Only drawback I suppose is money :)
 
I read the H beam rods clear just want to double check with somebody whos
done it already.As far as the rest of that,im good.:-DThanks.
 
I checked a few days ago with a supplier of stroker kits & they told me the H beam rods would fit without clearancing the block. It was an eBay auction & they didn't specify whose rods they were using but I'm pretty sure they were Eagles. I've also heard that the Eagle I beam rods don't need block clearancing either. But I haven't done it.
 
How do heads that flow 270 hit a wall at .510? Who flowed them? That set of numbers is not accurate. Reversion is not a head issue, it's a cam issue. But they do run into choke when things get too fast thru the port or turbulence is too great. In any event, a head that flows 270 is a very strong flowing iron head. Hell, it's pretty good for any aluminum port. If the head loses over .500, your max flow number is at least 30-40cfm too high. As far as stroking... did you sonic test the bores? the vast majority of 340s cannot be bored over .040 and have enough meat where they need it for a strong 4" engine. Plan on clearancing the block. Youmay not need to. But I'd plan for it rather than hope it fits.
 
I have Scat I-beams in my 4" stroke engine and they cleared the block without grinding with room to spare. But I paid the machine shop to check for rod clearance anyway. Usually H-beams will require clearancing and so will stock rods.
 
I run i-beams in my stroker,no clearance was needed..if you run h-beams the block needs to be clearanced..if its all apart now and you can afford it deffinately go the stroker route...
 
moper said:
How do heads that flow 270 hit a wall at .510? Who flowed them? That set of numbers is not accurate. Reversion is not a head issue, it's a cam issue. But they do run into choke when things get too fast thru the port or turbulence is too great. In any event, a head that flows 270 is a very strong flowing iron head. Hell, it's pretty good for any aluminum port. If the head loses over .500, your max flow number is at least 30-40cfm too high. As far as stroking... did you sonic test the bores? the vast majority of 340s cannot be bored over .040 and have enough meat where they need it for a strong 4" engine. Plan on clearancing the block. Youmay not need to. But I'd plan for it rather than hope it fits.
Click to expand...

Hi moper,the heads were done at a machine shop in Carroll,Ia.Been using him for years.The spec sheet was lost in a work bench oil spill 2 years ago so i no longer have that to go off of.The reversion may have started later,i think he said to go no bigger than a .510 cam to be safe.

This block was sonic tested when bored,BUT,we werent talking stroker then.
Reading my mopar books looks like they recommend another block for a 418.So now im thinking not to mess with it and maybe upgrade cam and rods
in my current engine.Thought i was going to have some fun with this:angry7:.Any
suggestions on the stock stroke setup?
 
You must log in or register to reply here.
-

Back
Top