71MercKid

Okay. I posted on here august last year, I had recently gotten a '71 Marquis with an N-Code 2V 429. Well. A few days ago, she spun a bearing, I instantly knew the sound and shut her down and had her towed home and haven't ran her since that day. My question is. Whats a good build to go with? I want the smooth idle still, but I would like to get a little more power from her. I know this obviously means running a new intake and 4bbl carb at the very least. The engine and C6 tranny have 134,567 on them both, but if I'm going in for the engine, the tranny is getting some attention too even though she doesn't need it. Preventive maintenance I guess. So. For trans. Rebuild, and a trans-go kit to firm up the shifts? I've read something about R-Code servo's/vacuum modulators? Is that the same thing or two different parts? What should I go with? I want full auto in drive but I would like something that will listen to me when I drop it to 2nd or 1st on the column. But the engine. Any recommendations on a cam with more punch to it? Heavy duty rod bearings/mains? Something that will give me more safety when I'm running her hard. I do drive my car, I don't baby it. Oh, and she has DOVE-C heads, which still have the factory everything. Still took lead additive. Any head work I should have done for easier breathing? She has stock headers with 3 inch straight pipe duals and some 70's glasspacks, she had a nice raspy sound to her. Alot of questions, I know but I want more than the advertised old 320hp and 460ft. lbs if I'm gonna be spending the money.

Paul Kane

As delivered, the C6 should instantly go into 2nd gear when you select 2nd gear. It will even start out in 2nd gear from a standstill if you have selected 2nd gear. Just sayin...

Engine: What you build depends on how much you care to spend and how much power you want, etc. I have a good recipe for a build that ought to get you around 350-375 real-world horsepower (which is probably about 100 hp more than the engine actually had before it died), and this build uses a lot of factory parts from various 429/460 year models. I think it might be good your your 71 Marquis. By the way, I have a 73 Marquis 2-dr and I'm building a very similar engine for it.

Sound like what you're looking for?

Paul

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F-250 Warhorse

As for the engine I am not much help, I have a lot to learn still. As for the c6, I have done plenty with those. My mods I recommend are this: if you want more rpm out of the upshift without manual selection, you can lighten up the governor weights and tune the vaccuum modulator until you get stiff shifts. This will also allow a downshift at higher speeds and shouldn't have a terrible effect on the driveability of it. A transgo is a nice kit, I have used many, they work well. Excellent instructions, and good improvement.
I never did the servo upgrade, the transgo should boost the pressure there slightly and if you want a real firm 2nd shift, take the big spring out from behind the servo, that will really shift hard then but only coming into 2nd. The servo on a c6 is for the band and the band makes 2nd gear.