Combo Advice 340

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1968FormulaS340

1968FormulaS340

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As some of you know I have a 68, 340 Formula S 4 Speed. I am returning the engine compartment to stock. I will be removing my large roller cam (won’t list the specs because it won’t work with my new combo).

What I have to work with is a 1968 340 (going to stay with this)

Fully balanced, blueprinted bottom end with professionally lightened and polished stock forged rods.

3.91 rear

Pro race ported stock X heads

11.5 compression.

What will be going on is.

Stock dual point distributor

Stock port matched 340 intake

Stock 4424s Carter AVS

Stock 340 Exhaust manifolds

TTI 2 1/2” X-pipe or H-pipe system with tail pipes

What advise do you have. I would like to have as much power as the stock look will give me. Think F.A.S.T. class
 
If it were me, I'd have a custom cam made, usign that info, plus flow numbers on the heads. "pro race ported" sounds like they are good, but you need cfm numbers to get a true idea. You want a cam with a wide centerline, say 112 or so, and that leans towards the exh a bit. Not too much overlap. That intake will hurt, because your ports are larger, and the intake's ports and plenum volume are still small. The exh manifolds arent bad. The carb will take some tuning, but it will work. In terms of FAST stuff, you need a MUCH larger engine..418 ish, plus having all the oither stuff max ported and/or extrude honed. And the carb professionally redone and setup...I'm assuming you meant in appearance only.
 
Yes appearance only. I don't plan to race in FAST class. Thanks for the Info. I understand it can be hard to find parts to tune an AVS. Is this true?
 
Cam? Custom grind for a F.A.S.T. class racing or something like it. Stick with the roller and call Comp Cams or Crane cams for what you want.

AVS Carb;

AVS parts are the same as a AFB. If it is an O.E. AVS, then you'll need to flatten or purchase new spring/piston/rod covers that are flat. The AVS rods are a tad longer than AFB rods, but will otherwise swap.
Use of AFB rods in the AVS with the stock covers will allow the rod to come out of the jet and run the engine crazy rich and also may not go back into the jet and jam up.
All parts should be easy to get from Edelbrock.
 
I would go with Moper. Stroke that thing!!! A 340 bored .040 over with a 4" stroker crank would be a 418. In a 68 barracuda that weighs about 3100 pounds with a 200 lbs. driver, it would scream. My 416 in my '69 dart is putting out about 500 hp at the flywheel and runs 11's weighing 3400 lbs with me in it. You could possibally dip into the 10's with traction and a good driver. Good luck.
 
Yes, stroke it. as for the dual point dist--- you need to keep ---or get elect. dist with a MSD 6AL---you will want the rev. limiter with a 4 speed. Go with the TTI x-pipe exhaust, it is the best fitting system money can and will buy. Get with INDY cyl. head, they can do cams for any spec. Call them and ask for Ken, he does the engines and will be glad to talk with you and get you what you need. As for the 11.5 comp. thats a lot for iron heads on pump gas you would have to run around 100 octane gas. I dont know if you plan to race this or just drive it. Also you could have the intake and exhuast manifolds xtrud honed. hope this helps.
 
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