turbotim23

Hi I bought a set of stock alum Lt1 heads at a swapmeet. These are heads that have never been on a car, valves and seats are new and don't need to be redone. I was thinking of doing some Mostly minor pocket porting, port matching and a little polishing inside ports. I was also thinking of having local shop either backcut stock valves or deepen seat throat angle to help the flow and possibly add better teflon valve seals. Is this minor amount of porting I'm thinking of doing worth it? One problem is seats are new I'm going to have to protect them when I port. I was thinking of sliding metal tube inside seat and port inside that. This summer I'd like to change the heads and add a hot cam kit. thanks Tim

reoch999

Home porting is possible, if it's something you're interested in doing for the "fun" of doing it. If you're just looking to save money, it's not worth it.

If you decide to give it a shot, my advice is talk to Ron (cousinartvette or something like that is his ID), and do a search for any posts on here and the LT1 f-body forums for anything by Nighttrain66. Also, if you can read some David Vizard stuff, he's not an LT1 specialist but he's got a ton of knowledge on small block chevy and a lot of it is applicable to the LT1 heads.

Here's the instructions I copied from one of LE's posts and organized into bullet points:

Porting Instructions

INTAKE:
· Narrow the intake guide boss,
· widen pushrod pinch,
· make bowl larger,
· raise the roof as much as possible,
· straighten thewall between the intake ports and if you have little or no porting experience
· do not touch the shortside at all. There is CFM to be gained if done correct but there is more to lose if not done correct. If you really know what to do to the shortside you are probably not reading this post anyway.

EXHAUST:
· Narrow the guide on the exhaust,
· widen the port above the shortside and you can
· enlarge the header flange slightly but make sure not to get it as large as the gasket. Theer is also a small bump on the shortside of most LT1s and if you can
· remove the bump with out lowering the floor and make sure the port goes strait up from the seat before the gradual turn. Just remove the bump only. If you can not remove the bump with out lowering the fkloor than leave it alone.

Do these things and get the best valve job that you can afford. The LT1 heads are so choked up that almost any porting will show some performance gain. If you are after XXX amount of HP or CFM you might not get it on your first set, If you jut wanna do them to do them or will be happy with 10-20 HP (depending on your skillz) increase than you can probably get that. There is more HP in the heads if done correctly but as I mentioned, If you are reading this (and learning things) you will probably not see the 35-60 HP (depending on mods) gain that is possible with other heads.

Good Luck

NightTrain66

When reshaping the guide boss, think of it as leading edge and trailing edge, like an airplane wing. Inside the chamber I didn't remove much material at all, just smoothed sharp edges and polished the roughness off.
Another piece of advice I found helpful, do one step to all 8 intake ports before moving on to the next step. It's easier to be consistant from one to the next if you do it this way.

Good luck!

cv67

Good post.

Getting 250ish intake and mid 180s to 200 cfm can be easily done with a stock valve/valve job LT1 head. I cancelled my photobucket so at the moment I dont have any pics but you can get them to work for most applications without going too nuts on them.

The low and mid lift #s (let alone peaK) wont be anything like a good aftermarket head but youll definitely feel it in the big pedal on the right; you can get them comparable to a larger valved Trick Flow head though. Youre not going to hit water unless youre a total idiot with the grinder just dont get greedy

turbotim23

Thanks guys It's winter and I don't have anywhere to work on my car till spring so I'm looking for small jobs I can do in the basement. Any one know of web sites that might have pictures of do it yourself porting. I have the tools and have done some porting before. What I need is the inside tips like what reoch999 listed. Thanks again Tim

reoch999

www.gofastnews.com Do a search for Dave Vizard. He's a regular there, with several technical articles including pictures. I doubt any of his articles have ever dealt directly with LT1 heads, but you can get an idea what a clean well-flowing port looks like. And if I'm wrong and he has done LT1 heads, memorize that article and send me a link!!!

Here's an article with a few good pictures of LT1 heads after porting: http://www.chevyhiperformance.com/te...ild/index.html

reoch999

Just came across a list of helpful websites I stored in my bookmarks and thought I'd post them here for you and anyone else who's curious. I'm sure there are other maybe even better sources out there, this is just some of what I found helpful in my research.

http://www.popularhotrodding.com/eng...ing_donts.html

http://www.gofastnews.com/board/tech...low-bench.html

http://members.***.net/gmarengo/ (click on the "head porting" link on the left side of the page.)

http://www.allpar.com/fix/holler/porting2.html

http://www.popularhotrodding.com/eng...ing/index.html