Opinions on a 340

AJ/FormS said
With 8.5 and open chambers and a cam to make you smile? It will never happen. It will make maybe 5% hp more than your 318 and the bottom will be soft.
-I would ditch those slugs.
-Like was said; zero deck flat tops and closed chamber heads. That will get you closer to 10.5 c/r.Then you can cam it.That will get you close to or into the 400+ hp. And thats where the smiles start.
-If you have to stick with 8.5s, then Id put some 318 closed chamber heads on it with a 360 2bbl cam and a smallport dualplane intake and a TQ to top it off. You will be smiling for 6 days or 300 miles.Then park it for a week.Repeat. Every time you drive it after the resting, you will again smile. Ask me how I know.
-If you fail to park it for the resting week, then sooner or later the smiling will end,and you will be be wishing you had put the flat tops in it,and the closed chamber big port heads, and a real cam, because even though its making plenty of torque, its way soft on top.
-It would actually run pretty decent with your plan, including the current 318cam.It will probably be a mid 14 second car.Mid 14s made me smile when I was 16. Big time.Its addictive. I quit spending money at mid 12s. It gets expensive in a hurry from there.
-I wouldnt want to be in your shoes, making this decision.
-And, like Rusty said, 8.5 will work in a DD. Just be really careful with cam selection.
-Too small is better than too big.No lumpity-lumps at 8.5. Well, let me rephrase that; I would stay away from the lumpity lumps at 8.5. Id be trying to keep the Dynamic c/r up.

Happy Wrenching

I need to stick with the 915 heads because it's what I have available to me. I scored a complete pair for $25 a few months ago. I'm thinking about ditching the stock 8.5:1 pistons and going with the 1971 pistons instead to up compression some. I talked to the guy who I'm buying the motor from and they're stock compression pistons for 1971 or 1972. He was going to build a '71 340 but ended up with this 72. So the pistons could be for either, I'll know for sure when I get my hands on the 340 soon and can measure them. I was going to swap in a 340 long block in place of the 318's and keep my carb and intake and all my accessories. I want to keep this on a budget because I'm a college student and don't have a ton of money to make this happen. But considering I can get a machined 340 block, pistons, rods, and a crank plus some other stuff for $500 and some change I think it's a good buy. The only other 340 I can find around here is for sale for almost $2,000 and it's not even a runner, it's just in pieces. The 1971 340's came with 915 heads if I remember right and they made good power so I'll probably use the 71 style pistons. Lets say that the pistons that come with the 340 are the 71 replacement ones. To get the short block together I'd just need the cam and lifters (bout $200), main and rod bearings ($50), gasket set ($60), rings ($40). I'd use the pan, oil pump/pickup, and timing set from the 318. The local machine shop will do the heads for $250. Thats $600 plus the cost of the initial purchase and $1,100 in total for the 340 long block. Then theres the cost of fluids and little miscellaneous nuts and bolts, I figure $100. Just swapping my induction and ignition over to the 340 long block should work right? I talked to Schumacher on the phone today and the 340 will work with their 318 mounts thats in my /6 K frame. Getting a 340 in my Dart for under $1,500 sounds like a good thing to me, and if I up the compression and choose my cam accordingly it sounds like it should run pretty good too. If I had more money I'd go all out with aftermarket heads and a different carb/intake setup and all kinds of other goodies. I'm just on a budget. I don't blame you for not wanting to be in my shoes making this decision, I only get one shot at getting this right. For now at least. I've been trying to hunt down a 340 for over 4 years now and to finally have one within my reach is a good feeling.