Lately I've been getting excited since my car, which has been down since december of 2006, is just about ready to be assembled. I was originally going to run completely stock heads but a new job has allowed me to open up my wallet some. I brought my heads to a local machine shop that has a lot of LT1 experience. They did some bowl blending, gasket matching, performed a valve job, installed my PAC-1518s at 1.780" (130 lbs), deburred all sharp edges, slight mill, and CCed the combustion chambers. There was no extensive porting, just some attention to detail in key areas.
Overall I am very pleased with the results. I decided not to get flow numbers but he said they would provide an additional 20-25 hp over the stock heads. Every little bit counts!

These are moderately high resolution (photobucket's max of 1024 pixels wide) and I believe cz28.com resizes them down to 800 pixels wide so they're going to be distorted a tad. Just click on properties and copy the image address if you want to see it full size.

On to the pictures.


combustion chamber
one side was 53.4cc and the other was 53.8cc. when the block deck height is checked we'll see if we can make it even.


Intake ports. you can see where they were gasket matched and some bowl work was done.


closeup picture of the intake port.


exhaust ports. more gasket matching and bowl work.


closeup of the exhaust port looking down at the valve.


closeup of the exhaust port looking at the roof.

 

here are some before pics...

 

The finish looks kind of rough.Maybe its just me.I would try and smooth a lot of that out some.

 

his exact words were "they don't look like glass but they'll definitely perform"
I don't think air really cares about what the surface looks like.

he has his own hand ported LT1 castings on his 383 camaro. with a hydraulic roller cam and stock LT1 intake it has gone 11.2 @ 121 blowing the trans up. Car is not a lightweight stripper, either. So I think I'll trust him.

 

Why wouldn't you...

That's a big boast!

Yes it does, they don't call it port AND polish for nothing. Ever heard of drag?

Who knows what mods are responsible for his times.

 

The intake doesnt matter too much,the exhaust side should be smooth.I am sure they are a lot better than stock.Good luck.

 

I think they look pretty good, you should definitely notice a difference over stock especially if you run a bigger cam. Don't listen to all the nay sayers, not everyone has $2000 to spend on a set of heads like others on this board, I'm all for "bang for the buck."

 

Anyone that KNOWS anything about head porting will NEVER say "polish" in the same sentence with "port".

The head port has whats called a boundary layer that hugs the port walls that the faster flowing air rides on, if the port is "polished" this cannot take affect.

If you ever see a port that has a mirror sheen AT ALL, throw them in the garbage.

David

 

Exactly, but don't take my word for it, ask the pro's.

 

The exhaust side SHOULD be polished and the intake side should at least be left without burs.

 

Because flow numbers do not mean anything to me. Horsepower does.
20-25 flywheel horsepower from a good valve job, bowl work, good gasket matching, and a point of extra compression? you really don't think thats attainable?
There is already a post below about this.
I know very much about his car. 383 with forged goodies (all american), his own ported heads, his own spec hydraulic roller cam, custom made 4" single exhaust, and proper set up. I stuck my head everywhere on this car. inside, underneath, and around. He doesn't have a hidden nitrous system. pretty simple setup that isn't even 100% dialed in. I would expect a 10 second pass from him, all motor, on pump gas, this year. how many LT1 guys can claim that?

 

Hmm, really? My ex port looks exactly like my intake port finish and they flow 230 cfm WITH NO PIPE...maybe I should call my head porter back?


David

 

smooth in "shape" is important. Smooth in "texture" is not. Exhaust being polished super smooth is not gonna hurt but it helks nothing. Most agree the intake should be 60-80 grit and that is about it. No gain if smoother and possibly hurt things since the boundary layer is thinner and gives the fuel a better chance to stick to the wall and seperate from air.

I can see 20-25 HP from a point of compression, good valve job, some bowl work and opening the PR pinch lil.

Not much removed from the port and you can still see the casting lines in the entire exhaust port so I would not think much more than a sand paper roll was done there. I would like to see the intake guide be ALOT narrower than what it is and with the valves in, it is really impossible to see what the valve job and bowl area look like.

All in all, I would expect the 20-25 HP increase you are looking for if there is a good valve job and nice bowl work. to go along with the extra point off compression. You should see about 10-12 HP from compression gain alone so another 10-15 from the portwork is about right.

Lloyd

 

thank you lloyd.

I got exactly what I wanted and paid for. If I wanted a fully ported set of heads, they would have been on their way to you... again!

Just wanted to show what the ports on a lightly worked set of stock heads looked like since most people post fully ported heads.