Porting Heads - And so it begins.......
Had these stock 5.3's flowed with the stock, super-tiny 1.89/1.55 valves. The guy that flowed them wants to learn more about the LSx stuff, so he has offered to flow test them for me for FREE if I share my porting techniques with him. It's a great deal for me considering he normally charges $60/chamber, per flow test. In reality, I'm shooting for numbers in the mid 290 range for the intake, and around 220ish, both at .500-.550 lift range. I got mid 270's out some LT1 heads, so this should be a cake walk with these "glory" heads,,,, at least I hope.
Anyway, I'm going to be taking many photos, and documenting the port work along the way. Thought maybe you guys would like to see the progress as it happens so I'll update as progress permits.
Here are the stock flow #'s @ 28":
lift........./ int../ exh
.200...... 136.... 105
.250...... 167.... 121
.300...... 192.... 137
.350...... 211.... 155
.400...... 223.... 171<-- became turbulent on intake side
.450...... 223.... 190
.500...... 224.... 203
.550...... 228.... 213
.600...... 233.... 217
.650...... 237.... 218
.700...... 239.... 221
EDIT, Here are the "after porting" flow numbers.
lift........./ int../ exh
.200...... 131.... 111
.250...... 160.... 131
.300...... 190.... 149
.350...... 217.... 168
.400...... 240.... 183
.450...... 257.... 201
.500...... 273.... 217
.550...... 283.... 228
.600...... 289.... 235
.650...... 295.... 241
.700...... 298.... xxx
Here's some pics of the stockers as-is:




And no,,,, I'm not porting these in my kitchen.
Mike
Last edited by Mikey 97Z M6; Dec 15, 2006 at 08:05 PM.
Robert
Robert

These pictures suck because my camera doesn't like to take close up shots. It can't focus that close. I have another cheapo camera that zooms closer and takes better pictures close up. I'll use that one for all my other photos. I'm hoping to get started on these this weekend.
DrkPhx, Ya, I believe the Manleys come stock with a backcut on them already. I remember when I was doing the LT1's, the guy doing the seat cuts suggested a back cut on the exhaust valves and it picked up 8cfm between .450 and .550 lifts. Quite amazing what a small change can make in flow.
Mike
Again, thanks for the tips.
Mike
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Nate, I cleared my PM box also...
Here's some pics from today's porting:
Roughing in the intake entry. Sorry these turned out a bit dark.



Here I just did some rough shaping in the bowl area, blending the intake porting into the bowl and shaping the valve guide area.



Here's some pics after I completed all the shaping, then hit the entire port/bowl with a cartridge roll. I'm fairly pleased with how this one turned out. These LSx heads are a walk in the park compared to porting an LT1 head. I have about 2.25 hours into this port and it was my first one. The rest will go quickly if this flows worth a ****.





Tomorrow I'll be doing the exhaust runner and unshrouding some valves in chamber area. Fun stuff..........
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Eric, ya, I'll be finishing up this chamber and then it's back to the flow test again. I'm gonna drop off the head on Mon. and I hope to get it back by the following weekend. I'll probably finish up all the exhaust runners on this head tomorrow, and might start with some simple stuff on the other head during the week. Most of the things I would change (if any) are going to be in the bowl area and short side radius so there is quite a bit of work I can do on the other head while this one is getting tested.
I'll be happy if they achieve 290+ cfm at .500-.550 lift. We'll see........
Mike
What are those bits on your die grinders? They look like they would take away material crazy fast..
What are those bits on your die grinders? They look like they would take away material crazy fast..
Those bits, or "burs", are specific for porting. The super aggressive ones are for non-ferrous material, the others are for ferrous metals (alum/iron respectively). I use the alum burs for shaping, and the iron burs for smoothing, blending, then the cartridge rolls (sand paper) for final smoothing. If you're interested in porting, contact a local machine shop and find out who supplies them with their burs/bits. Summit racing has limited sources for them also, or find an online supplier. They're not cheap though, and average between $15-25 each depending on diameter and length.
Mike
Last edited by Mikey 97Z M6; Dec 10, 2006 at 02:45 AM.
Nate
I have pictures of the new work from yesterday, but I forgot my damn camera at home. If I have time, I'll swing by there after dropping off the head so I can get some more pics up this afternoon.....
Ackattack, I'll mention it to Dennis, but I allready know what he's going to say about it. He's flowing them for free, so I pretty much gotta go with whatever he decides to do.
Mike
Mike

