Chebby heads, Mopar heads...

[Nacho-RT74]

I'm wondering why the BIG difference at least published specs on those when talking about flow on heads.

what is the argument on that ?

[tan top]

stock for stock ... except HEMI  ... i hate to say this but Chebby heads are better flowing ..especialy  BB  ...fords are better flowing also 
  had a flow chart somewhere

[Mopar2Ya]

I'm no engine builder, but isn't it true over all flow isn't the only thing to watch for?

[WingCharger]

The Magnum heads are better flowing than Chevy LT-1 heads.
MoParAction did a write up on it.

[Nacho-RT74]

I guess you say about new Magnum heads, but I'm talking about our original ones. Does look that EVEN PORTING them, still Chebby heads in stock form are WAY BETTER than ours!

so why Mopar made that in that way ?

[maxwellwedge]

Street Torque baby! So what if the Ford ports were bigger back then - they were pigs!

[Ghoste]

Yep, port velocity has a little bit do with it. 

[Nacho-RT74]

further technical explanation will be great

[b5blue]

Are you talking about Chevy big block (rat) square or oval port heads?  The main problem with ether from a technical standpoint is that they don't flow at all when your Chevy breaks! But seriously there are both to "pipe in" on for "rat motors"...Nacho I can call a good friend tomorrow and find out for you...Bob has raced them all!

[1969chargerrtse]

Since were on mopar heads, whats the deal with the stupid idea of allowing the exhaust studs to enter the water jacket?  They leak. 

[Ghoste]

I'd have to say that I have never ever had that problem. 

[Silver R/T]

Since were on mopar heads, whats the deal with the stupid idea of allowing the exhaust studs to enter the water jacket?  They leak. 

If you change your exhaust/ do headers and don't drain coolant yes it will leak.

[b5blue]

They can be a bitch if there old and worn out holes (think there is some kind of joke there..but that's not where I'm going with this...).You do have to drain the system and clean/dry things out (no..not another one..) then put the right sealant....to fix them if they leak 

[Nacho-RT74]

 

[Chargerrtforme]

My stock 906 heads leaked also. I know it's a common problem. I resealed them with another brand sealer and they still burn off antifreeze on start up.

[Nacho-RT74]

never had a problem with that yet.

I have known about Ford Heads, at least 351 Cleveland engine, the flow is TOO HIGH, SO HIGH that you need to arrive around 8K RPMs to make them work as should be, but low end power is very poor.

I'm anxious to heard more technical post about the volume flow and speed flow or port velocity differences making that the reason of why Mopar heads are a litle bit low flow beside Chebby heads

[b5blue]

I promise to call Bob tomorrow Nacho! He will know more than I could remember! (had a bad day..2 jobs to go bid and unknown flat tire that I couldn't find the leak on) I had a set of those 351 ford heads...the freaking ports were huge!! They looked like you could roll eggs through the intakes and plums out the exhaust!

[b5blue]

Hey Nacho ! Talked to Bob and he explained that the rat heads are basically a shorter run. More of an turn inside but less distance to travel to the cylinder. The oval port heads are great for up to 6,000 RPM ("more torque") but that's it..then they choke off. The square ports are for anything over 6,000 RPM on up but both "can ported to flow 340 with very little work". Sounds like wedges are "in between" both heads with less of a angle inside but a longer "run". I told him that I thought they didn't "flow" more...it was just that Chevy sucks so much it seemed like more! We had a good laugh and he said to let you know if up against a "rat motor" the heads will help tell you how it's set up. 

[Ghoste]

How do you tell square port from oval port externally?

[maxwellwedge]

The one that doesn't chirp the tires untill 6000 RPM are the rectangular! 

[Nacho-RT74]

sorry, I didn't get it 

[b5blue]

The intake runner should be rounded on oval, it's been 30 years since I swore off GM for good...but square's "look" more like our intakes and the oval's look like the Ford 351 C intakes Nacho mentioned if that helps and I remember right! If I got to I'll go check a little "jet" boat my friend has...  he's running a 454 roller rat in that!