hey guys, im looking to rebuild the 340 in my dart over the winter and I could use some help. i would love to get an honest 450 hp out of it. I have about 3500 to invest. I was thinking maybe a stroker kit and some eddys but thats most of budget right there, maybe just put some money into port work on the x heads i already have and spend the rest elsewhere, kinda torn any advice appreciated
looking for some help on a 340 build
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Brian Hafliger
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Not going to happen on that budget. We did a nice 340 with street ported eddy heads, 10.2:1 and comp solid FT cam 240's @ .050, good headers, carb ignition and it made 455.
It's not easy getting a true 450HP...well it is but doing it with stock ported heads makes it more difficult.
Brian
autoxcuda
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Was that the comp 274S cam?
I am looking very hard at that cam for my 416 with ported Edelbrocks, and M1 single plane. I got to pull the trigger on a cam ASAP.
autoxcuda
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Bump.
Brian was that the 274S cam??
Anyone use that cam in a 340/360 or stroker?? http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=670&sb=2 :help:
Brain is so right. Getting that HP level isn't exactly OOTB stuff thrown on a engine. Porting the iron heads would be cheaper in away over getting Edelbrock heads OOTB and then off to the machinest for a check out.
Stroking the engine is great for torque production! But, that's a bit of coin to spend and all you have is a bottom emd with stock parts up top or just a lack of parts.
Building a 340 up should start with a excellent short block. Once you have that done, then turn to your heads where the rest of the budget will get eaten up. The heads being the problem in this... so far... is that stock heads need a good bit of port work. Paying for it can be costly.
Consider your going to start with a bare head and besides clean up and magna fluxing for cracks, your looking at all new parts there after and then porting labor. While, IMO, it is probably worth it to port the OE heads over a Edelbrock head purchase and then machinest check and correction (If need be) the ceiling level and overall flow curve of the OE iron head may not be as nice as it should be.
Even so, if it can be, it may not be as nice to drive as it could have been. OE heads are cpable of this power output.
Brain has some nice Indy heads he works on that have very favorable flow numbers. Bennifits are the heads are new through out and are worked on by Brian who has experiance in this feild. The Indy heas are reasonably priced to start with. And still so after Brian works on them.
(Discloser; I normaly don't provide such (raving like) reviews of members here and there work.)
Stroking the engine is great for torque production! But, that's a bit of coin to spend and all you have is a bottom emd with stock parts up top or just a lack of parts.
Building a 340 up should start with a excellent short block. Once you have that done, then turn to your heads where the rest of the budget will get eaten up. The heads being the problem in this... so far... is that stock heads need a good bit of port work. Paying for it can be costly.
Consider your going to start with a bare head and besides clean up and magna fluxing for cracks, your looking at all new parts there after and then porting labor. While, IMO, it is probably worth it to port the OE heads over a Edelbrock head purchase and then machinest check and correction (If need be) the ceiling level and overall flow curve of the OE iron head may not be as nice as it should be.
Even so, if it can be, it may not be as nice to drive as it could have been. OE heads are cpable of this power output.
Brain has some nice Indy heads he works on that have very favorable flow numbers. Bennifits are the heads are new through out and are worked on by Brian who has experiance in this feild. The Indy heas are reasonably priced to start with. And still so after Brian works on them.
(Discloser; I normaly don't provide such (raving like) reviews of members here and there work.)
moper
Well-Known Member
All depends on what you have. If it was me and the engine is running ok now but stock, I'd use some of that money for solid bolt ons, and pocket the rest for a later engine build. You need about twice that to do a nice 340, a little more than that for a decent stroked package.
IIRC it was a XS282S in the 340 Brian built.
http://www.compcams.com/Company/CC/cam-specs/Details.aspx?csid=671&sb=2
I'm going to have to agree with what's been said so far. You need almost twice that much to get to the 450 hp mark with a 340.
I have a complete 340 sitting on my engine stand almost ready to go into my Challenger that I believe will be solidly over the 400 hp mark (maybe not 450 though) , and I have a little over $5k into it at this point. My build looks like this
'68 340 block , .060 over, stock forged crank
Stock reconditioned rods and ARP bolts
Stock windage tray, HV oil pump, Kevko oil pan
KB 243 pistons, 9.9:1 compression with 65cc chamber and .039" gasket ( pistons are .018" over the deck, btw)
Lunati Voodoo 60404 (hydraulic flat tappet), duration 276/284 (advertised) lift .513/.533
308 heads, 2.02/1.60 valves, ported and flowing 264 cfm at .500"
Edelbrock RPM Air Gap manifold
Holley Street Avenger 770 cfm
Hooker Super Comp headers, 1 3/4"
Smith Brothers push rods
Harland Sharp roller rockers
There's a few goodies on there, but it doesn't tell the whole story. I did this with a budget in mind, and the Harland's were bought second hand (they were used as a mock up set by another member), the intake and headers were bought used. All were nearly half of new cost. I had to go with custom pushrods because of the length needed and the adjustable arms (ball/cup set-up).
And, I would do a few things different if I had to do it over. I'd go forged pistons, first of all. Nothing wrong with the hypers per say, but when I did the short block I didn't have the heads (not a good idea, btw) and I ended up doing more work to the heads and going with a bigger cam, so in retrospect I wish I had the forged pistons for piece of mind.
I would also have used RHS heads. After I bought a set of 308's, had them opened up to 2.02/1.60 and ported to flow 264 cfm @ .500", I spent more money than a set of RHS heads would cost, and flow a little less than the RHS heads would. Not entirely my fault, as the RHS heads weren't available when I bought my 308's (been at this build for too long).
My suggestion would be this. If you have to rebuild the engine right now, build a solid short block. Get forged pistons, have everything magnafluxed, bored, square decked, etc. And use a milder cam, a stock set of heads, exhaust manifolds etc. You won't make 450 hp, but you'll have a solid engine, and you can probably be close to your budget.
When you can afford to go back and spend $1,500 on heads, $700 on headers, $500 on a big carb etc you'll be able to swap in a big cam, bolt everything on and be in the ballpark for your HP goals. The only thing you'll really lose money on is the cam, I'm guessing you already have a 4 barrel manifold and carb to go with a mild 340.
I have a complete 340 sitting on my engine stand almost ready to go into my Challenger that I believe will be solidly over the 400 hp mark (maybe not 450 though) , and I have a little over $5k into it at this point. My build looks like this
'68 340 block , .060 over, stock forged crank
Stock reconditioned rods and ARP bolts
Stock windage tray, HV oil pump, Kevko oil pan
KB 243 pistons, 9.9:1 compression with 65cc chamber and .039" gasket ( pistons are .018" over the deck, btw)
Lunati Voodoo 60404 (hydraulic flat tappet), duration 276/284 (advertised) lift .513/.533
308 heads, 2.02/1.60 valves, ported and flowing 264 cfm at .500"
Edelbrock RPM Air Gap manifold
Holley Street Avenger 770 cfm
Hooker Super Comp headers, 1 3/4"
Smith Brothers push rods
Harland Sharp roller rockers
There's a few goodies on there, but it doesn't tell the whole story. I did this with a budget in mind, and the Harland's were bought second hand (they were used as a mock up set by another member), the intake and headers were bought used. All were nearly half of new cost. I had to go with custom pushrods because of the length needed and the adjustable arms (ball/cup set-up).
And, I would do a few things different if I had to do it over. I'd go forged pistons, first of all. Nothing wrong with the hypers per say, but when I did the short block I didn't have the heads (not a good idea, btw) and I ended up doing more work to the heads and going with a bigger cam, so in retrospect I wish I had the forged pistons for piece of mind.
I would also have used RHS heads. After I bought a set of 308's, had them opened up to 2.02/1.60 and ported to flow 264 cfm @ .500", I spent more money than a set of RHS heads would cost, and flow a little less than the RHS heads would. Not entirely my fault, as the RHS heads weren't available when I bought my 308's (been at this build for too long).
My suggestion would be this. If you have to rebuild the engine right now, build a solid short block. Get forged pistons, have everything magnafluxed, bored, square decked, etc. And use a milder cam, a stock set of heads, exhaust manifolds etc. You won't make 450 hp, but you'll have a solid engine, and you can probably be close to your budget.
When you can afford to go back and spend $1,500 on heads, $700 on headers, $500 on a big carb etc you'll be able to swap in a big cam, bolt everything on and be in the ballpark for your HP goals. The only thing you'll really lose money on is the cam, I'm guessing you already have a 4 barrel manifold and carb to go with a mild 340.
Good advice blunblu. Makes absoulte good sense.
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