chamber size on max wedge heads

[6T5]

I just cc'd my 286's and they are 94-98cc. This car I bought also has -15cc dished pistons.........anyway it all comes out to about 8.3:1 compression...WOW-stand back!LOL

The cam that's in it is 255degree @ .050. No wonder this thing is a turd.

ALL THAT being said. Is there a cam that is specifically designed for these really low comp engines?

I know there's a lot of motorhome stuff that's low comp.

Looking to hear from someone that has actually installed one "back-to-back" so to speak.......or done cranking psi test...etc.

I've read all the manufactures websites and read a million blogs "...she runs like heck..." I'm hoping to hear some definitive info.

Thanks very much.

BTW- it's in a street car, mild gearing and converter.

 

[GearAddict]

There are a few out there. I don't have any specific experience with them myself, but I have been looking into this for my low comp 383.

I believe Hughes has one that it popular at the moment and I believe some of the Edelbrock grinds are geared toward waking up a stock, low comp motor.

All that said, do a little research on cam companies you like and start calling their tech support, I understand from many posts here that they can be very helpful.

 

[GTX MATT]

Did you recently buy this car? If so do you mind if I ask where it came from?

I wouldn't put a really small cam in. You can certainly go smaller, but I wouldn't try to make it run good by sticking a really small cam in. If you put something like 220 @ .050 its still going to be a turd. Big ports to kill low end, small cam to kill top end when the ports want to go to work. 94-98 CCs is huge, are you sure thats right? I believe they should be around 86 CC. If so you really need to install domed pistons or have the heads milled at least a little to help fix this. I'd also run a steel shim gasket. How far below deck are the pistons? The right way to fix this engine is with more compression.

And who the heck put this engine together? Does it have a cross ram? Max wedge manifolds? Give us more info!

 

[Meep-Meep]

Yes, Max Wedge head chamber volumes are larger than 906 heads due to the tulip intake valves. 90-ish CC is about right. There are plenty of cams designed for low compression or just put a lung on it.

 

[Dibbons]

I read decades ago that the tulip-shape intake valves were considered obsolete and were being replaced by a more conventional shape. I thought the motivation for that was because they were heavy, and were an impediment to a lighter valve train, but don't quote me on that. Replacing them, assuming you are using the tulip shape intakes, might help raise your compression a bit.

 

[lewtot184]

tulip intake valves have been obsolete for a couple decades. i believe they are an obstruction in flow. i do think they work ok on hemi heads but not wedges. wedges prefer the nailhead design. there's not enough information on the "[email protected]" cam. hydraulic cams that big will be awful. lsa, installed centerline, etc are needed.

 

[6T5]

Thanks for the replies guys-

-yea, chambers are easily 96cc+. I think NHRA accepted minimum, after considerable milling is about 87cc.

-that is EXACTLY my concern about changing to one of these "magic" cams for low compression......it could so mild that the big ports are lazy, slow air speed..etc. Perhaps even a bigger dog than it is now.

-I don't know how this engine got so mismatched. It's the way I got it.



Thanks for your interest. Here's the whole powertrain combo.

-426 / .030 w/ -15cc semidish.

-zero deck...had .040 gasket in it

-286 heads. 2.08 and 1.81 (I think they put the small ex valve in to clear the bore without notching the block. My block is not notched.)

-Voodoo 60305 hyd. INT-242 /.533 EXH-252 /.552 LSA110 intake close 47ABDC(106cl)

-It has an ancient Weiand low-rise (I mean flat!) single carb manifold w/ max wedge ports. It's divided plenum (not split plane) ..open with center divider. It's weird.

-Holley 950hp

-1.75 headers.

-3.91 with tall tire (29") Which is actually more like a 3.55 once you do the math.(most street radials being 26-27")

I have an original x-ram. I'd like to put that on and maybe fenderwell or maxie exhaust.

Good comments. Thank you. ..can't tell you how much I appreciate, polite, constructive help......not that smart *** stuff (like on that other site). If I want funny I'll just jump over to the humor page (which I do)
-mild (maybe stock) converter. 2500?

 

[383man]

Do you know what pistons are in it ? Are they supossed to be the factory 11.0 comp Maxie pistons ? Ron

 

[Garys1969RR]

Sounds as if the entire build is a mis match of parts. If you want low end torque and power, stick to what the factory specs were for like a 67 440. That is, 75 to 80 cc closed chamber 915 heads. You can use the larger 2.14 intake valves, and the 1.81 ex valves. Or stick with the stock 2.08 int/1.74 ex valves. Run a cam similar to what was used on the stock 440 magnum. I think they were around 268/284 duration, .450/.458 lift. Int/ex. Run a flat top piston at about .017" deck clearance, with a .020 steel shim gasket. The factory intake can work well with stock heads. Just ask Meep Meep! Put on a good carb and headers and you should have a real screamer! Don't forget to re curve the distributor and set timing to 20 initial, 38 total.

 

[6T5]

They're a Ross with semi-dish, -15cc

 

[Garys1969RR]

The large ports of the max wedge heads were designed for higher RPMs. But you also would need the factory cross ram intake and dual carbs for it to perform well. Also, they were built with either 11 to 1 or 12.5 to 1 C Ratio. High compression needs a bigger cam, low compression needs a milder cam, generally speaking.

- - - Updated - - -

Put in dome pistons, get the C/R up and that will help a lot.

 

[Meep-Meep]

I think if you swap to the 915's as Gary mentioned you would do much better overall and without changing the pistons. I can say with certainty that a 426W with zero deck pistons and a couple of valve reliefs will yield 9.6:1 CR with 915's and a comp gasket. And that assumes a 10.7" deck height. Now I did run a Maxie on the street years ago with some hot cam and it ran fine for the most part. Probably because I had my foot to the floor most of the time!

That Weiand intake is a vintage piece! And does it seal to the block end rails? i.e. no valley pan required. Those divided plenum single plane intakes don't like overlap so just changing that out should do some good.

Yes, I have the same info that states the tulip valve is not as good on the wedge heads but fine or preferred on the hemi. Clearly the valve angle in relation to the port has something to do with that.

 

[Garys1969RR]

And put the cross ram intake on it. With a lot of compression and a good tune, the thing should really fly!

- - - Updated - - -

That is, with the higher C/R and max wedge heads and the cam you have in it.

 

[63 fury maxwedge]

When I first got my Max Wedge it ran fine but, all power was at the bottom and was over around 5000 rpm. The engine was built with 9-1 compression, 1963 286 heads with 81cc chambers, comp cams 21-213-4, 260H, original crossram, original carbs.
I ended up rebuilding the engine as a stroker, I have posted some specs of the present build ( Max Wedge stroker ).
I think the early 286 heads were at 81cc and some of the later recast were the same, I think the latest castings were changed to 96cc.

 

[6T5]

Mine are 96cc or so and original 286's. I spoke with the guy who bought them new and used them on all his Mopars since. Must have been great back in the day.

I'll search your build, thanks. Thanks all

 

[GTX MATT]

I see two ways to fix this without making some sort of sacrifice really - change the pistons out for something with a dome or change the heads to an aluminum closed chamber, the Eddy RPMs, Stealths, or Indy EZs. If your heads have no port work you will make more power/torque with the aluminum heads. IMO if you change the pistons you still have a little bit of a mismatch to the combo. It will make power, but you're still running smaller headers and a smaller hydraulic cam for a set of heads that are going to want to spin to 7K. The standard port aluminum heads will outflow the Max Wedge heads with a smaller port which = more torque. With any of those heads you will have a real nice street engine. I'm not sure if you're running the Max Wedge heads for a reason though.

Also ditch the intake.