DOOE-R Heads / exhaust port plates

What all is involved in installing a set of the plates and how much can be gained with them?

IMO a waste of money if using typical chassis headers

Right now I run a custom set of 2 1/4 bbc flanged fenderwell exit headers with Charlie Evan's plates.

IMO that's as good as it gets with a factory head

so your saying that what I have is about as good as it gets and having the heads cut for the price motorsports plates wont give me any more flow?

Are you running a cast iron head class?

yes I looked into the ex-514's but $3500 for cheapest casting he has right now is a littl emore than i want to give cuz they would be awful heavy in a car if I gave up mud racing

Well that's a tough decision to make, with typical car headers your wasting you time with port plates IMO and your also destroying the value of a set of cj heads adding the plates.

What comshaft are you running?

custom cam from cam research gross lift .772 intake and exhaust and the 278/286 @ .050 but not positive.

Also I have two sets of these heads the set I run I had ported from virgin castings and they turned out very good. The other set i purchased already ported and they were hogged on, flow numbers were not so good for ported heads they also had a crack in the exhaust port that has now been repaired. If I do this I think I would use the not so good set.

Their probably something to be had with a larger split on the cam rather than adding the plates plus having a max effort port job done by a pro.

Do you have any compression or fuel rules?

I did have the heads done by a pro and his flow numbers were very close to what is published to max flow and again i am not sure about the cam numbers I wil call and see if they still have that info. No compressioin rule. As for fuel must be gasoline. In my othe rthread "Starting to plan for the future I have copied a set of the rules I run by they are pretty vague.

How many inches and how much compression are you running now?

Right now I am at 495 inches with (dove-a block bored 4.44 with a 4 inch stroke crank) and I run 14.5 : 1 compression. I am looking into going to a 4.3 stoke crank but not sur my block will go any bigger bore will sonic check it this off season. As funds allow in the future I am planning on purchasing the a-460 block but with just buying a home this year my funds are tight so that may take a year or so to get to.

OK I called and got my cam info as stated it is a custom Cam Research grind lift is .772/.772, duration is 278 intake/286 exhaust, with a 110 lobe seperation.

May consider adding another 10-12 degrees to the exhaust and widen the lc to 112-113ish

I would not use the port plates, they will weaken the head. The better route is to raise the exhasut port floor with that head. The port can be picked up at least 40 numbers by doing this properly. You will also need a custom flange for the headers.

Bret

Bret Powell wrote:I would not use the port plates, they will weaken the head. The better route is to raise the exhasut port floor with that head. The port can be picked up at least 40 numbers by doing this properly. You will also need a custom flange for the headers.

Bret

Let me see if I can find pictures of the heads you worked on.

Picture of the raised exhaust floor via 2007 BBF Bash and Tech

Bret Powell wrote:I would not use the port plates, they will weaken the head. The better route is to raise the exhasut port floor with that head. The port can be picked up at least 40 numbers by doing this properly. You will also need a custom flange for the headers.

Bret

Sorry to hijack here, but I'm gonna do it anyway.....

Bret, it's nice to see you here..... Hope you decide to stick around awhile, I always like reading your posts.

Greg

No problem Greg

Mr Powell can you explain how the plates weaken the head?

To install these plates, you have to machine the exhaust ports off of the head to a depth just past the head bolt holes. There is a floor left below the exhaust ports for indexing the depth of the plates, the remainder of the head is then comprimised because this machining will go into the water jackets thereby weakening the exaust side of the head. Hope this helps.

What kind of cost would there be to braze up the ports like in the pictures above?

lghting94 wrote:What kind of cost would there be to braze up the ports like in the pictures above?

We had a set done about twelve years ago, at that time it was $300. I don't have a clue what it would cost today, but I do know it was worth the effort. Picked up the numbers a bunch.