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My new 340 Engine

Posted By: Chal340

My new 340 Engine - 09/11/09 02:50 PM

This winter I'm going to rebuilt my 70's 340 engine. What do you think about these parts.

Carburator : Holley street avenger 81670
Intake manifold : Edel Performer RPM Air Gap
Heads : edelbrock Performer RPM
Rocker arm : comp cam CCA-1322-16
Pistons KB 243 Hypereutectic
New forged steel rods
stock 70's Crankshaft
Camshaft :comp cam XE268H or hughes 1523AL
New melling oil pump, ARP bolts, new water pump and FBO ignition.

HP and torque?

It will be for street/strip, for the moment I have a 2.76 but I think to buy a 3.23 or 3.55. I have a 727.
In France pump gas is 87 octane and C/R will be probably around 10.2.

Thanks
Posted By: ademon

Re: My new 340 Engine - 09/11/09 03:39 PM

Looks good, I would call Hughes or comp and give them your engine specs and also tell them you can only get 87 octain fuel and let them pick a cam that will work the best with the pump fuel. you should be fine with aluminum heads and 87 if you keep it right around 10.2.
Posted By: patrick

Re: My new 340 Engine - 09/11/09 03:41 PM

if your block is stock deck height, the pistons will be .018" out of the hole. I'd get the closed chambered edelbrocks, and run a fel pro 8553-pt. those are .054" compressed, and will net you a .036" quench distance).

you probably don't need adjustible rockers, to be honest. stock ones should work fine with either cam. in the states, octane rating is an average of RON and MON values, IIRC in europe it is RON, so your 87 octane I think is closer to 89 or 90 octane here. the hughes cam might be a bit small for that compression and octane. it probably will work, but you may need to retard the timing some to avoid pinging (the tighter the quench distance, the more knock resistant it will be). I'd look at the lunati voodoo 60403 cam, personally. it should still work fine with the stock edelbrock springs.
Posted By: Crizila

Re: My new 340 Engine - 09/11/09 03:44 PM

I can attest to that 1523AL as being a great cam for your set up. Lots of bottom end torque. With 3.55's, probably low 13's or high 12's.
Posted By: Dartcuda

Re: My new 340 Engine - 09/11/09 04:30 PM

For just a little bit more money you can stroke it .
Posted By: Challenger 1

Re: My new 340 Engine - 09/11/09 05:22 PM

Quote:

if your block is stock deck height, the pistons will be .018" out of the hole. I'd get the closed chambered edelbrocks, and run a fel pro 8553-pt. those are .054" compressed, and will net you a .036" quench distance).

you probably don't need adjustible rockers, to be honest. stock ones should work fine with either cam. in the states, octane rating is an average of RON and MON values, IIRC in europe it is RON, so your 87 octane I think is closer to 89 or 90 octane here. the hughes cam might be a bit small for that compression and octane. it probably will work, but you may need to retard the timing some to avoid pinging (the tighter the quench distance, the more knock resistant it will be). I'd look at the lunati voodoo 60403 cam, personally. it should still work fine with the stock edelbrock springs.



I recently built a stock block/bore 340 with stock crank and rods with the KB243 pistons. They were .029 out of the hole. I used open chamber Eddie heads. I think I figured it would be right around 10.1-1 comp? The motor runs great, I do run it on at least 91 fuel though. Using a MP.474 cam in it.
Posted By: patrick

Re: My new 340 Engine - 09/11/09 05:37 PM

Quote:

For just a little bit more money you can stroke it .



more than a little...those 340 KB pistons are ~$250/set. a dished 350 stroker piston, you're looking at the KB745's which are ~$200 more...those use thin rings, which are usually $40-50 more than the standard 5/64" rings....you're looking at $280-1000 for a crank (cast or forged), IIRC they use chamfered (more expensive) rod bearings, then for him you have shipping to europe....
Posted By: Chal340

Re: My new 340 Engine - 09/11/09 07:13 PM

shipping and customs 20, 25 %, and I want to stay on 340.
Posted By: Chal340

Re: My new 340 Engine - 09/11/09 07:41 PM

what's the minimum quench distance?
The open eddie heads are better for a 340?
Posted By: Challenger 1

Re: My new 340 Engine - 09/11/09 08:32 PM

Quote:

what's the minimum quench distance?
The open eddie heads are better for a 340?


Only if your pistons is more than .015" above the deck.

Like I said, mine were .029" above the deck with a stock untouched block, crank and rods.
Posted By: patrick

Re: My new 340 Engine - 09/11/09 08:41 PM

minimum depends on a lot of things including bore diameter, skirt clearance, rod material, and max RPM. the general rule of thumb is .040", for something with steel rods, smaller bore & tight skirt clearance (less piston rocking), and kept below 5500 RPM, I'd feel comfortable with .035" or so.
Posted By: Chal340

Re: My new 340 Engine - 09/12/09 08:54 AM

Quote:

Quote:

what's the minimum quench distance?
The open eddie heads are better for a 340?


Only if your pistons is more than .015" above the deck.

Like I said, mine were .029" above the deck with a stock untouched block, crank and rods.



Ok, I don't know how is my block for the moment,so it will be safer to buy open chamber with these pistons KB243 or buy pistons without deck out of the hole. Is there hypereutectic pistons or only forged pistons without this deck out. If I make a mistake in my order, I can't return (shipping expensive).
Posted By: Challenger 1

Re: My new 340 Engine - 09/12/09 11:47 AM

I'd use those pistons with the open chamber heads,IMO
Can you assemble the short block with a new piston and check it out before you order heads?

Posted By: Chal340

Re: My new 340 Engine - 09/12/09 12:45 PM

Yes, I'm going to make this, check and buy heads open or closed. thanks.
What do you think about hp and torque
Posted By: Chal340

Re: My new 340 Engine - 12/04/09 10:42 PM

I measured my block, with actual pistons ( with 1.73 compression distance and 0.40 over) they are 0.093 on the hole at right side and 0.077 at left side.
So with new pistons like kb243 or TRW L2316F, with 1.84 compression distance, I will have a positive deck height of 0.017 and 0.033.
If i put my block at the same height with this piston, maybe 0.040, can I use open chamber eddelbrock heads ( 60179 ) with a thick cylinder head gasket (0.053).What do you think about this?
I can't calculate the quench because I don't know the height of the hole of this cylinder heads.
With this positive deck, 0.040, it will be ok for the rings?
Posted By: can.al

Re: My new 340 Engine - 12/04/09 11:31 PM

..In an A body your going to have a little street Rocket with this build and your cam is well suited to 3.23 gears.
At this level i think stock heads will work fine even with 1.88 intakes ..
.....al
Posted By: 4BBodies

Re: My new 340 Engine - 12/05/09 06:11 PM

My 340 has similar specs, with 3:23 gears and a 2800 stall converter. Since I almost wet my pants after trying it out the first time, I'd say you will be pleased.........

Attached picture 5648324-(99-08)340Assembly(Feb22,2008).jpg
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