906 heads sufficient?

[Mr4Speed]

hi guys,

I am not building a dragracer, but a nice 63 Savoy MW Clone.

i am gonna build an engine for my car in the near future; what i want:
1963 426 c.i. wedge, compression +/- 10:1
going with a crossram with 2 edelbrock 650 carbs
MW exhaustmanifolds with a 3-inch exhaust
nice cam, haven't decided which one yet, has to have a nice lumpy idle.
i have manual brakes on the car
I have a nice set of 906-heads; are these heads sufficient for this engine combo? again, i am not building a racecar, i just want nice power and durability.
thanks for all the replies,
Marcel
the Netherlands

 

[lewtot184]

more times than not people will steer you towards an aftermarket aluminum head. the real issue isn't the need for a higher flowing head but the cross ram intake that doesn't flow a lot of air. the intake will be a choke point for good high flowing heads. if you use a cross ram with the same port window as a 906 head it may flow even less than an original max wedge port window intake. if it were me and i wanted to use what i have i'd keep my 906's (do some port and valve work), use some quench dome pistons for the open chambers, pick a moderate camshaft, use 600 edelbrocks, and go have fun.

 

[Meep-Meep]

906 heads are great but as mentioned above you have to deal with a port mismatch assuming you are using a factory MW cross ram. The other restriction is the small cross section of the port where the push rod goes through, but if you just want to build a fun street car for not a lot of money go for it. I would spend some time blending the roof of the port to the intake but also be careful to not break through. This is where the aftermarket aluminum heads may actually help your situation because I think there is more material at the top of the port to allow for enlarging. Also, a cam that gives a nice lumpy idle will require more compression so make sure that is addressed early on in the build.

 

[Mr4Speed]

thanks guys; i am gonna use a repro mw intakemanifold, with standard size ports, so not with the maxwedge-size ports; i will get them gasketmatched or mildly ported but that's it.
I will stick with the 906's and have fun with the car!

 

[lewtot184]

thanks guys; i am gonna use a repro mw intakemanifold, with standard size ports, so not with the maxwedge-size ports; i will get them gasketmatched or mildly ported but that's it.
I will stick with the 906's and have fun with the car!

this probably makes the most sense. the manifold you buy probably won't flow 250cfm so you don't need a 280-300cfm head. 240-250cfm is pretty easy with an iron head. i've seen this combo a lot with the cruiser crowd and they seem to be satisfied.

 

[Meep-Meep]

Wasn't aware you could get a MW cross ram with normal BB sized ports. In that case, bolt it together with the 906's and drive the wheels off it!

 

[Mr4Speed]

yes, they are available; A&A transmissions, Mancini, they all stock this intake.
What kind of horsepower could i expect from an engine i am planning to build?
( A rough guess?? )

 

[Meep-Meep]

Assuming you don't kill it with low compression and too much cam I'd say 380 at the wheels easy. That should put a 3700 lb car in the 12's and still allow the wife to make it to the grocery store without trouble.

 

[65 Plymouth Satellite 426]

Be Sure Those Heads Have 2.14 Intakes & 1.81 Exhaust Valves! The Key To The Max-Wedge Heads Design Were Those 1.88 Exhaust Valves!

 

[Mr4Speed]

a friend of mine is an enginebuilder for a tractorpullingteam; he builds methanol-hemi's all the time, and he is gonna build my engine; he was talking about putting bigger valves in the heads. He could fix that fairly cheap.

 

[Meep-Meep]

There is little use putting bigger intake valves in the 906 head unless you open up the cross section area at the push rod. Just pocket port as per the DC specs. Adding the 1.81 exhaust will be a benefit if you massage the port opening accordingly and use a 2" primary header.

 

[Mr4Speed]

ah okay; i will use the repro max wedge exhaustmanifolds, are they smaller than 2 inches?

 

[minnesota guy]

If you can get 452 heads go with those! They have hardened seats and the ports are much nicer,improved castings, and easier to port! I have ported both 906 and 452's. I will take a 452 anyday over a 906 and they flow the same if not better for less work. Pocket porting should be the bare minimum.

I agree with Meep-Meep on using larger valves (2.14/ 1.81) unless you open up the port and straighten it out by the push rods. Straighter the route to the valve, the better in these heads. I have my own ported 906 heads on my 1971 Cuda that I race at BIR. Be careful in the intake valve pocket so you don't hit water! Been there, done that. Mine flow 260-270 cfm or so.

 

[lewtot184]

mopar muscle magazine had a very good series of articles on reworking iron heads. it was done by steve dulchich. well worth reading and debunks a lot of myths. if you want flow past .500 lift big valves are almost a must. i use a set of mopar stage 5's done by dwayne porter of porter racing heads.

 

[Mr4Speed]

i have got a ton of magazines,so i will jump in on those in the weekend.
thanks for all the help!

 

[IQ52]

The Max Wedge Cross Ram intake manifold in standard 440 port size will flow an average of approximately 280 cfm. A really good port job on the 452 heads will flow around 290-295 cfm and we have 906 heads on the shelf with the standard port window that flow 320 cfm average @ .600" and 330 cfm average @ .700".

 

[Mr4Speed]

you mean unported 906 heads?? What kind of cam would be sufficient for my set-up?

 

[robinsonwr]

My only problem with the combination is not the cast iron heads or cross-ram it is compression ratio and cam choice. Your first post said 10:1 compression with cast iron heads, right? I think 9.5:1 would be better with cast iron heads and pump gas. The cam selection cam help or hurt the overall compression. Be careful we all want performance and not a detonation monster or pinging beast.

 

[IQ52]

No, these are fully ported 906 heads that still maintain the stock gasket size. A stock 906 head will flow approximately 230 cfm as do the 452 and other factory heads.

Before any cams could be recommended I would think that transmission ("Mr4Speed" could be hint as to the transmission), torque converter stall speed, gear ratio and tire size should be considered. It sounds like you are having your 906 heads modified and the flow of your cylinder heads should be considered too.

What rpm range do you want to run? What style of cam, flat tappet, roller, solid or hydraulic? What style of rocker arms are you considering, factory stamped steel or adjustable?

What fuel and final compression ratio are you going to use? The cam duration will effect the fuel you will be able to run.

 

[Mr4Speed]

hi guys, the plan is to have a streetable engine; if a compressionratio of 9.5:1 is better..than that will be it. I have a 413 engine, which will be bored to 426, using 906 heads with standard steel rockerarms.
I have a 3.91 suregrip in the rear and original 7.5 x 14 tyres ( oh yes, they are definatly too small ) and a 4-speed.
I would like to have a nice lumpy idle if possible. It is not gonna be raced, maybe once a year for fun.
I can buy 98 octane gas everywhere in Holland