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70Mach1rb

70 Mach 1 4V Heads VS 2V Head Set Up - How Fast Can You Go?

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My 70 Mach 1 I just bought is, was an M code car which of course came with 4V heads and a 4 barrel intake. The engine I have that came with it is a 351 Cleveland with a 2v head set up and an Edelbrock Performer Intake designed to run with and work with 2V Heads.

Since I believe the cam is just one size over the OEM stock cam, I'm not sure how much added performance the 2V set up will gain from this intake. Even though I have heard some summit reviews saying it has really boosted their hp from a 2 barrel intake and carb now they have a small 4 bbl and the much larger intake.  So yes that would make sense that there would be an improvement. 

How much is the $2 dollar question? Would it be shameful to drive a factory rated 300 hp car that cannot make 300 hp? LOL 

I'm certain with the right cam and heads and intake you could just about pick what hp you wanted. AS long as you had a big block!

Trouble is I need to know whether or not to sell this powder-coated Performer Intake and rebuilt 2v Cleveland heads on eBay and go with the 4v original, Or just drive the 2v and hold the heads and intake for later in case I have a buyer that wants to give me more than the thing is worth some time down the road. :)

Which is why I ask about this. I have a set of 4V heads along with a stock 4bbl intake. With that set up I'm sure to make 300 hp. AS it was rated that from the factory @5400 rpm. 

I know what one system will do as far as high-end torque. I don't know what the 2v system will do and how if any better on the low end. Anyone out there with a set up such as this one?

Any advice? What would you do if it were your mess? 

Cordially,

Rick

351 V4 Cleveland Engine.jpg

Edited by 70Mach1rb
Forgot pic

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So Is the car otherwise original?

really not sure what you are trying to achieve is it originality or power?  

M code was 300hp measured in gross flywheel no accessory load etc. if you want power you need to say how much more you want   Is it an arbitrary 30p fwhP as that isn’t anything magical.  

I have never seen anything that discussed what an m code actually delivered or performed like when new.  

Why don’t you dyno the car and see just what the current combo delivers before worrying about it. With the Cam, intake and exhaust and it’s probably doing as well as the old stock combo.

if you put on the 4v you will need blue thunder intake and a decent cam to wake it up and then be in for roller rockers new valves springs etc etc.  & before you know it you’ve dropped $3-4k. And most people will be asking why you just didn’t put on a set of alloy 3vs

 

 

good luck 

ps personally my M code is staying with the 4vs but with a 408 stroker kit and a SCM manifold so it looks stock but should run way over 400 fwhp with a relatively mild cam. 

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My 69 had a 351C with 4V dot heads (open chamber) when I got it. Has a mild cam, 600 Holley and stock manifolds. 3.25 diff and FMX. I was never impressed with the power off the mark and it had no chance of lighting up the tires with the traction lock. I recently rebuild the engine and changed to 2V closed chamber heads and a compression ratio of 10:1. A big difference off the mark and will now light up the tires. mission accomplished.

I have heard mixed views on 2V vs 4V but from my experience the 2V gave a lot more torque which may also be the increased compression ratio.

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I once put a set of 2v heads on a 4V shortblock, also had headers and and an intake with a 600 holley. The car was a 1970 XR7 Cougar with an FMX (B&M Shift kit), I think the mufflers were hush thrush on the stock exhaust. Anyway the car came off the line and was a screamer all the past any legal speed limit.

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