I had a plan to do some port work and put in bigger valves on a set of heads for my 71 350. My problem is that I have never done any porting work before and in my part of the world, there aren’t many tahat have worked on upgrades for buick 350. So my question is. Is there anyone or any shops in the US that’s still takes on porting 350 buick heads? How much would porting and bigger valves cost? I am not looking for any race porting but just so I can get up to 350-380 with a good setup Thanks! HD
You should list your area location , someone may know a shop near you. But any machine shop that does some race work would be better, more knowledgeable. If your near Michigan there is finishline Motorsports. And a few other places. Am&p in Kentucky has lots experience if you can get in. TA performance can do them in Arizona. And TA is developing aluminum heads for 350. But no date set on release. I ported a few sets , but no clue on flow just some home porting. Actually doing a set currently. Trying a few different tools. Read up on other combos and what they produced for power so you can guage what else you need to do to reach your goals. Your going to spend atleast 800 for springs, valves and other needed work on heads. As far as the 71 engine you will need to rebuild with better hi compression Pistons to reach that goal. And need oil modifications.
Jim W. at Tri-Shield Performance is working on a 350 build for me. The heads were ported by Greg Gessler years ago but Jim got similar/better numbers from a set of heads he ported for his 350 build here: http://v8buick.com/index.php?threads/tsp-level-1-350-buildup-info-and-dyno-results.153248/ Generally, the numbers you can expect from a performance oriented port job are here: http://www.v8buick.com/index.php?threads/buick-350-head-airflow-numbers.323659/ Two of the 3 listed gentlemen in that thread, Jim Burek and Greg Gessler, no longer appear to be in the head porting business. Please ignore the fact that I misspelled Jim Weise's name in that thread. As Andy noted, there are others that can also do the work and the aluminum heads from TA will likely flow better than irons.
Chris Skaling in canada is the best head porter i know of... He is porting my alum 350 heads once they arereleased
Regarding the cost of shipping heads ... They already flow enough to make your HP goal. A valve job with suitable geometry and bowl blending any shop/person can do is all you need, along with your build plan. I'm going to seriously question shipping them around the globe...UNLESS you do not have or cannot get a set.
http://www.automachperf.com/350Stage1heads.html It’s worth a phone call to see if this is still available
Isn't the 'reference point' for hp potential out of heads 2 hp per CFM of flow? More work has to be done to get closer to that number, but is doable. Older factory heads flow ~198 CFM intake, and newer heads ~188 CFM, straight out of the foundry mold. A good valve job and unshrouding is said to add 15-20 CFM, with some simple bowl blending about that much more, depending. All said, 215-225 CFM on older heads and 205-215 CFM on newer heads is achievable with very little work. These numbers correspond to a potential power output between 410-450 hp, so I'd say 350-380 hp would be pretty easy to achieve as long as your other components are a good match.
Using the basic information we have thus far, the conversion (standard valves to larger "Stage 1" valves) indicates a '15 hp' increase, which would equate to about a 7.5 CFM gain over factory flow. The "SS" upgrade indicates 'up to 50 hp gain' on top of this, and says it's 230 CFM intake flow, which would equate to about 25 CFM over stock, and so on. These numbers correspond to factory CFM flow ratings, albeit a bit generously stated suggesting stock heads flow at 205 CFM intake. I suppose factory stuff would vary depending on casting imperfections, showing that removing these alone would net worthwhile gains, much less anything else added to it. It could therefore be safely stated that Buick 350 heads flow a true 200 CFM from the factory with little to no work done to them, and would be good for up to 400 hp in this basic state.
