Performance AMC blocks

[1970amx]

I am defintely not saying that you can't make power with iron AMC OE stuff, you can.

But it is a proven fact that if you want to make lots of power there is no replacement for cubic inches. You don't see modern pro stocks running small cubic inch engines do you ? No....they run as many cubes as legally possible in their class.

Another thing is making reliable horsepower. You have to spin a small engine hard to make as much horsepower as a larger cubic inch engine.

As far as the Iron heads outflowing the race oriented (not edelbrock) Indy 401-1 or Brewer heads....they are not even close. The 401-1 Indy heads flow right at 400 cfm and the Brewer heads even more than 400cfm.

That much head flow needs more that 400 cubic inches to take best advantage of it.

A fully worked AMC iron head can be made to flow around 300 cfm or so but that is with a HUGE amount of work that is not cost effective compared with the Indy 401 SR (stock replacement) head. The 401SR (stock replacement) head can be made to flow around 350 cfm with a max port job. But they will flow 300 or so cfm with just a moderate cleanup of the ports. By the time you payed for a professional to max out the Iron head you would have more money in it than a set of Indy SR heads cost.

If you want an AMC Iron head to flow more than the 300 cfm ballpark the only way to do it is with the cut them up...section out multiple castings and weld the pieces together tricks like Wally Booth did. Again not cost effective with modern Aluminum race oriented castings on the shelf for sale.

[1970amx]

I am not going to debate you. I don't like typing that much.

You are stuck in the old technology days of the early 70's. There is a lot more available than that now !

I am not going to be stuck in the 9's forever. Next year I am planning on running in the 8's with no power adders whatsoever and I am going to do it with 500 cubic inches and big flowing cylinder heads. And I will do it realiably turning a lot lower rpm's than a smaller motor.

No I don't run any power adders what so ever...no NOS, blower, or turbo...it's motor only....405 cubic inches with a flat tappet solid lifter cam. My car is a backhalfed Spirit that weighs in at 2840 pounds. And I built it all myself !

[Holeshot]

Not stuck in the old technology days, not hardly.

But I am very proud of what the AMC designers created and I like to display it for all to see. Anybody can burn up bucks like the bowtie or ford guys have to.

I guess it just depends on what you are wanting.

Looks like you are going racing, while I am going street machining.

A low ten street AMX is fine for me. Having it all AM, and using "period pieces" (like the Ultra Ram, R4B, & Street Ram) is icing on the cake.

The 401 can put out around 600 HP with AM heads, crank, block, rods, & without any high buck mods, and stand up to around 1000 HP when sprayed. That get's you into the 9s before spray.

The thing you are getting from more bore is more torque, and at a lower RPM, as the horsepower decreases, and at a very high cost (if using Indy heads or the Indy block). That's all I'm trying to say about that.

Any Dyno program (most are pretty reliable) will show that the HP goes down as the cylinder size (or stroke) goes up, all other input variables remaining the same. The power band goes down (to a lower RPM), the peak torque reading increases, also at a lower RPM. The opposite is also true, to extreme RPMs that are unreachable. Tho I do know a guy who ran his all AM AMX over 9000 RPM (he never made a full pass w/o blowing something up).

Personally, I stay away from any special combos made up from Chevy or Indy parts, etc., and stay with what AMC designed so well. The fully ported Indy SR heads flow only slightly better than fully ported AMC heads until the valve is over .600" lift, and then they get a bigger advantage. Pretty expensive per HP cost. Especially when you figure the added expense of lifting the valve to .800" or more. I'd rather save that money and put it towards the other AMX, or any of a thousand other areas it can be spent.

But then, I like "old technology" AMXs, too. Nothing like a stock appearing motor, that puts out 600 HP (950 if sprayed), to show to the boys after dusting them.

Not arguing with you, we all are here because we like AMC. You are using aftermarket & I like factory. So be it.

[1970amx]

Not arguing with you, we all are here because we like AMC. You are using aftermarket & I like factory. So be it

I couldn't agree with you more !

I wish you the best of luck blowing away the Fords, Chevies, and Mopars with your AMC.

I love the look on the other guys faces when an AMC beats them !

Have a good one !

Rob

[tarior]

Boy...I sure didn't mean to start a fire there
I would just like to see a solid, performance oriented, stock dimension (maybe a little more deck height, for improved rod angle, not more inches), cast iron block. Face it, guys, when you are racing,sh!t will break sooner or later, and the supply of blocks is far from inexhaustible. With all of this renewed interest in AMC, I see the supply of 401 blocks drying up quite soon. Even those blocks are only good for 750 hp (or less) in sustained operation, such as in the roundy- rounds or road racing.
We need a solution that is more practicle than $4200 aluminum blocks.

[John Martinez]

Larry Wycoff, is getting in excess of 800 HP out of stock block sleved and bored to 440 slug. He is using MOdex crank with 4" stroke. He get like 440 cubes or a little more. At 8500 rpm he is putting out in excess of 800 HP no adders.

But larry is going to go Blow Alchy and he will be using a 550 cu in hemi to get there. Even though Indy has offered him an alum block he feels more comfortable with the hemi platform due to past uses and aftermarket knowledge. This will be dropped into his tube chassis with AMC body.

Good luck to both of you. You both are doing AMC proud. Now if hankrod pumps up the turbo all bets are off.

[jeepsr4ever]

Now if hankrod pumps up the turbo all bets are off.

[jeepsr4ever]

We have a guy here locally that runs a 1400hp AMX. I think it may be the fastest AMX I have ever seen. He has a blown Hemi in it and probly 80K into his motor. I think he is still married as well

[Gremlin4ever]

A stock replacement block in 401 would be excellent!

Then I could just get a new block and go standard bore with the new pistons and rings instead of searching for .010 or .020, dang I hate going .030

[Migzilla]

Dang somebody beat me to the punch. I was thinking that the last time I checked 401 wern't that plentiful. I would be nice to get a cast iron block that you didn't have to roll the dice on. No more having to dig thru junk yards you could just pick up the phone order one. May be even start under bore and have the buyer machine what bore they want. Just and Idea or maybe I'm .