head bolt bulge in runner?

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754door

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I've finally started porting my 360 heads and was wondering if it is possible to remove the head bolt bulge in the runner next to the guide? on set of 596 heads with out hitting water or affecting the heads strength by the head bolt area.
Was going to port my heads a little more because they have a slight bowl port and the pushrod pinch was opened up a little bit and it has bigger valves 2.02

Any guesses On what it would flow right now. my guess is around 215 to 220cfm at around .500 lift. will find out tomorrow hopefully.
 
You shouldn't hit any water there but you can't remove it all or you'll go through into the valve cover area. Ask me how I know.....

Take it down a little and smooth it out and leave it at that to be safe. Same goes for the pushrod pinch area and the valve cover bolt protrusions. I found out the hard way that core shift also happens with heads. Or maybe their molds aren't exactly right on. Nevertheless I measured how much I could safely open up the pushrod pinch area on one and and ported it out and had no problem but on the intake runner adjacent I went through the casting. Seemed to be at least .050 thinner on that one. Luckily I have a buddy that repaired my screw up. After that I measured each one individually.

My X heads had minor bowl porting when I first started on them. Really all that was done is the guy that did the valves cut deeper into the pocket area so their was no lip there.

I opened up the pushrod pinch as much as I felt safe and shaped the valve guides and straightened out things the best I could. After doing these I know why guys charge so much to do this. It's very time consuming.

Here's the numbers before and after. You'll notice the exhaust numbers are a little low. That's probably because I took too much off the floor. Live and learn and leave the exh. floor alone except to grind off the high spots and polish it.

Lift Int. Before.............Int. after...........Exh. before........Exh. after
.100----60........................64....................50...................53
.200----120......................129...................104.................107
.300----173......................188...................131.................135
.400----210......................236...................143.................155
.500----220......................243...................146.................165
.600----215......................248...................148.................170

BTW: A good valve job with the right angles and back cutting the valves helps quite a bit too. That gave about a 5-8 cfm increase throughout on mine.
 
How much guide shaping di you do mine is still casting almost all the way around. he took a little off the end I will find out what they flow tomorrow It took my longer to take them apart because are valve spring compressor broke an we had to fix it. I will try to figure out how to post pics tomorrow. I think they will do around 220 or so. also there is a straight up and down casting line right on the side of the bowl still.
 
Did quite a bit of shaping on the guides. Here's a picture.

To post pics you can't use the quick reply feature. You have to click on the "Go advanced" tab. Then when it loads up below the message screen is a grey box that has a "manage attachments" tab. Click on that and it opens a window to load pics.

My X heads 005.JPE
 
Something I have always wondered about. When you guys do your bowl work do you cover the valve seats with duct tape or something to avoid damaging them or do you just use a slow speed & are REALLY careful?
 
yes you did.I tear droped it like you did to one of my 318 heads and it flowed 217cfm and it did 177cfm stock. This is with full port.
 
when I did mine for my head porting class I didn't and I didn't knick them that much I just reground them after I ported them.
 
Same here. Just have to be real careful around the seats. I also do the porting before and have the seats ground after to take care of any small nicks I might make.
 
they did 216cfm at .600 and 210cfm at .500. It turned out was a better than stock all the way by about 15 cfm. I think there is alot of room for improvment. I think I good get it to around 250cfm with some work.
 
If the valves have ever been ground they might have a better valve job than the factory sent them out with. That'll make them flow better. You should be able to get them to 250 or real close. Maybe even better. I don't know how much experience you have but I don't have much and I got mine right flowing at 250. I've been told they can flow alot better than that if you know more what your doing. BJR has posted some tremendous numbers on the ones he does.

How were the low lift numbers? In specifically the .200-.400 area. That's where the valve spends most of it's time so that makes the most difference in how your engine runs.
 
.100 66cfm
.200 121cfm
.300 167cfm
.400 210cfm
.500 210cfm
.600 216cfm

my other 596 heads did 196cfm .500lft

still have to do the exhaust tomorrow.
 
Small block heads (OEM) take the most time, and most cutters to get the profile and high numbers. I removed most of the guide boss from the runner. This gets very tedious/time consuming the further one gets to that horrendous casting lump on the roof. As for the seats: Just take your time. You don't want to snag a cutter.............
Found little material in books, however, Mopar used to sell porting templates for the '308 castings. But use caution. These would be a guide only. Give you an idea on your's what should be looked at. I spent a lot of time on my first final bowl, and then made my own templates.................
 
There is a small block chevy one that i have that has a lot of general stuff that will give good guidance on mopar heads or any other head.

It is called "How to build and modify small block chevrolet heads".

I got 246cfm on a set of magnum heads with a 1.92 valve
 
This is a set of 302/318 heads that I just did a week ago

Int. 1.78 Exh. 1.50

.100 76 77
.200 111 113
.300 175 122
.400 201 126
.500 204 128

this was machine cut and a good valve job only, no hand grinding.

This is a set of 915 fully ported with 1.88 intake valves

.100 94
.200 180
.300 222
.400 241
.500 280
.600 283
.700 278

This just gives you something to judge how well your doing, and progressing.
 
do 915s have the head bolt bulge in them like the 596s. Also do 596s have the same potential as the 915s and any other
small block heads.

I haven't done any porting on my heads a shop in andover did them about 2 years ago just so everybody knows. and I just flowed the way they did and now I'am going for a more fully ported form.
 
All small block 340/360 heads are similar in port shape from the factory, for production use. 273/318 heads are similar in port shape but in a smaller version. The 318 heads above were 120 cc's on the intake runner and the 915's were 167 cc's, the 318/302s started at 118cc's and the 915's started at 150 cc's.
 
BJR Racing said:
This is a set of 302/318 heads that I just did a week ago

Int. 1.78 Exh. 1.50

.100 76 77
.200 111 113
.300 175 122
.400 201 126
.500 204 128

this was machine cut and a good valve job only, no hand grinding.

This is a set of 915 fully ported with 1.88 intake valves

.100 94
.200 180
.300 222
.400 241
.500 280
.600 283
.700 278

This just gives you something to judge how well your doing, and progressing.
Click to expand...

You wouldn't by chance be talking about the heads you did for me would you? LOL

Did I leave the flow number sheet for my heads at your house? I can't find it anywhere and I have looked all through my truck.
 
754door said:
.100 66cfm
.200 121cfm
.300 167cfm
.400 210cfm
.500 210cfm
.600 216cfm

my other 596 heads did 196cfm .500lft

still have to do the exhaust tomorrow.
Click to expand...

That's not bad for stock. Right there with my 340X heads. That goes to show that all the stock heads are pretty close.

I see Bobby (BJR Racing) posted some of his. Man I wish I could get them numbers.:tongue9:

To Sublimeswinger. I haven't been able to find much written about porting them either. The first set of heads I did was allmost 20 yrs. ago and for a 327 Chevy. One of the magazines had an article on how to P&P your small block chevy heads and that's all I have ever seen. Fast forward 20 yrs. and I did my 2nd set, my 340X heads. Going by memory I did the best I could and they turned out decent. Not record breaking but a nice increase still.
 
mullinax95 said:
You wouldn't by chance be talking about the heads you did for me would you? LOL

Did I leave the flow number sheet for my heads at your house? I can't find it anywhere and I have looked all through my truck.
Click to expand...

Mullinax,
I didnt find it here and I thought that you put it in the truck? I can make you another sheet up if you like and yes they are your flow #'s.
 
(Quote: fishy68)
I see Bobby (BJR Racing) posted some of his. Man I wish I could get them numbers.:tongue9:


But you have to think that I've been porting heads for 30 years too, and I hoped to have found something in that amount of time.:)
 
BJR, the numbers you posted for the 302 castings-- How many HP are they capable of? I know it will depend on a lot of other factors but a basic 318/360 with street trim. Also is there a basic flow/hp scale. For a rough guide only. Kinda like the one that was on the carb boxes with a cid/rpm/flow graph.
 
dartjack,
This is what SuperFlow gives as a HP equation, air flow @ 28" divided by 1.67 to get to flow @ 10" and then X by 3.44 for HP. So this is what I would do, add all the flow's up to the valve lift by .100 then divide by the amount of lift then use the equation above, or it would look like this.
76+111+175+201=563 divided by 4 =140.75 then divide this by 1.67= 84.28 X 3.44=289.92 HP
 
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