Alrighty I need some serious help!  Back in April of 07, I purchased a 1970 Pontiac Firebird off of ebay as my first project car.  The car was listed as having a 400 with a 4bbl.  Well stupid me lol didn't do my research, won the car and when I finally decoded the engine, the engine code stated it was a Pontiac 350. The 4bbl intake and carb were added sometime between 1970 and today(I did know 350 only came 2bbl).  I was deeply disappointed that it was too late for ebay to help me get my money back since the auction ended a few months ago.  I later decided that this was the engine i'm just going to stick too since it was numbers matching with the car. I am preparing an engine rebuild but I want a nice set of heads to spice things up a bit (since compression ratio on a 350 is 8:1).  I have researched and can not find any hi-po heads for anything under a 389.  I was told that even though those heads are for 389+ cubic inches, they will still fit on my motor but I need to be completely sure. I have had people tell me to just put a 400 in it but I do not want to do this. I did see in HPP's article of a Pontiac 350 being capable of 462 raw horsepower, but can those heads be used without the motor being bored to a 383? Does anyone know who can make special heads for a 350 or if those 389+ heads will fit? Thank you


One more thing... I want to build my car up to today's standards (Like I want the performance of my car to at least keep up with a LS-1, LT-1, Mustang GT, or just all out stomp 'em!) in a 1/8 or 1/4 of a mile.  If anyone has any ideas, please let me know! I do want to keep the 350 motor and try to keep the 3 speed auto (only keeping it for matching #'s reasons). I am a college student so I do have a tight budget! All the money I save goes to my car lol.  Its going to take time but I think it will be worth it at the end.  

Rather than mess around trying to find iron heads that'll cost you, I'd just get a set of the Edelbrock aluminum Pontiac heads for your motor. Lighter weight, better ports, you can't lose.  

Two points to consider here.
First, you say you want to keep it #'s matching, That means all the numbers, if you want it to retain any collector value. The original heads will do for a nice cruiser if you have them rebuilt with a mild resurfacing and good 3-angle valve job, match them with a cam that matches the rest of the car (ie: carb,intake, torque converter, rear gears, tire size and weight). Add a 4bbl carb and intake (stock or Edelbrock Performer are good choices) and dual exhaust, you can easily remove the 4bbl and put the 2bbl back on if you keep it and the motor remains #'s matching. All this leaves you with an engine that will make decent power on low octane pump gas, which is all we really have anymore!
Second point, the 383 based on the Pontiac 350 is NOT a budget build by anybody's definition, Edelbrock heads alone are almost $2000 a set, plus the different head bolts and round port manifolds or headers that are required to bolt them on. As well, Edelbrock doesn't recommend them for 350's because their ports are too large for the smaller motor to make any low end torque, all right for a high rpm screamer or a very well thought out stroker like the 383. I'm not bashing the 383 build-up, it's cool to see what people who have the skill and resources can accomplish with a motor so many people dismiss as a boat anchor, just that I don't see this as a budget oriented option for a typical street cruiser.
The 350 is a good little engine, I have one myself and you can check it out at Reader's Rides on this site, when I get some track time in the spring, I'll update my car's profile with results.  

Sorry, One other thing, after re-reading the 383 article (it had been awhile since I read it), I realized that Ken Brewer had used production based #16 heads with some serious mods (Ferrea valves, CNC porting, shaft mounted roller rockers, filled heat riser crossover....). The price quoted for the heads was $1500 and another $800 for the shaft rockers. Definitely not low budget in my book, but way cool if you can afford!  

WOW!!! Haha don't think ill be doing a 383 stroker then lol yeah this is kind of a budget build.  I most likely won't have the car numbers matching but would like for it to be close.  If I replace any of the parts, I always will keep the originals.  The car already has a 4-barrel carb and intake with pro flo dual exhaust (never even heard of the brand, must be way before my time, but has 2 pipes going into one muffler and back out as 2) and a performance cam.  Don't know how much power it is producing as the current state of the motor is pretty bad (lots of sludge after numerous oil changes with the oil only having maybe 3 miles on it, dies a lot at a complete stop) so it needs a rebuild.  I will add an edelbrock performer intake during the rebuild so I won't need the adapter so it should clear a ram air hood. Now I remember you saying in the other forum that 400 heads will fit on my 350? Would you recommend this or just keep the 8:1 heads already on it? I just want something that will keep up with todays muscle (or at least 90's muscle). I found some HO 670 heads off of a 67 GTO for cheap but the guy doesn't know if they will fit on my motor. Don't think ill be getting edelbrock heads, too much money!!! lol. I looked at your 79 Bird and I have to say that is a beautiful formula you got there! Hope you don't replace the front fascia with a bandit front (seems like everyone around here is doing it). I almost got an 80 model but I lost the bid. Thanks for all the info barney, it is really clearing up my confusion with my motor lol. Ill be adding pics up of my car in a bit  

David, no threat of me changing my Bird's fascia. I figure these cars are getting old enough that people (especially younger ones) don't remember how they looked and they need to be kept looking original. For example, Rally II's, Honeycombs and Snowflakes can't be beat by any aftermarket "me too" rims and modern custom paint colors just look wrong on old cars. Just my opinion!
The 670 heads will work on your 350, but there is the question of non-hardened valve seats( for unleaded fuel). Some guys say they have run for years without them, some say it's a must have item. Your choice.  

I agree, I especially don't get this g-machine trend going on with the cars being slammed with ridiculously sized rims, there ruining a good muscle car! Only thing I might do is put torq-thrust d's on the bird but i'm keeping the snowflakes that are on it right now (not original for 70, but I think they still look good on the car). One thing i'm really debating is what to paint the car cause I don't like the gold color at all! I want to paint it Palladium Silver but I know, not original numbers haha. Well Ill see what I can do about those 670 heads, I still have to pay tuition and books for school and I won't get my tax return in time since another person wants those heads too lol.  

Hi you can get a good list of pontiac heads at wallace racing .com some # to look for are 18 these are 1968 350 heads that are 64cc and there are a lot more that will do a good job yours are most likely #11 that are rated at255 hp the #18 are rated at 320 hp some times on ebay you can pick these up pretty cheep  

Ill check that out, I have been looking at heads on ebay, just seeing how much they go for on there and they are pretty darn cheap!  Well I talked to my dad about it and he said something about cutting down the heads will increase compression, is this true cause i've never heard of this process? He said my uncle cut his heads on his 69 Charger to increase compression so I may have to give him a call lol. Thanks for the tip, ill keep my eye out on em!  

It's true, milling the surface of the head reduces the volume of the combustion chamber slightly, in turn increasing compression ratio. However it is slight, you won't go from 8:1 to 10:1, but you may get 8.4/8.5:1 depending on how much you take off. Wallace racing has a chart for this as well. Lots of good info on their site.  

Thats perfect, Barney I just got done looking at my book "Original Pontiac Firebird and Trans Am 1967-2002 Restorer's Guide" by Jim Schild, very good book, I recommend checking it out!  I just got done reading the 70-73 section and I found out the compression is really 8.8:1, so with my heads milled i'm looking to get around 9.2:1 which is quite satisfying to me. Thanks for the recommendation on wallaceracing, I got the chart and website saved on my computer  

Alrighty, I think I finally came to a conclusion of what to do about heads, and thats to Port n Polish them and to mill the stock heads.  I just got one more question!!! Does anyone know how much this is going to cost me haha? Or is it even worth port n polishing/milling stock 350 heads?  

I would skip the porting and polishing for this application, just have the heads rebuilt with a quality 3-angle valve job and milled enough to get a good gasket surface, then leave them alone (except of course, new valve guides and springs and valves if needed). You could easily spend the price of aluminum heads if you pay for someone (who knows what he is doing!) to port your heads.  

I'm know i'm going to need new springs for the heads and everything.  I went to the machine shop (I think i'm going to let them do it) a few months back and priced out my motor $850 for a basic rebuild with the cylinders bored .30 over + another $150 for springs, valves for the heads with a mild cam that comes with the package (which I already got a nice cam, just tell em to keep the one I got). Well after all I think I'm just going to keep the stock heads and fix em up, I can always put performance heads on later down the road.  Thank you again Barney and everyone who helped me, ill keep updating in my profile, hopefully have some pics of the rebuilt/painted motor within the next few months, y'all take care!  

I would have went with porting the heads and a 5 angle valve job.A performer intake a good set of headers as well as a 600 to 650 cfm carb. but may be I am posting this to late.Also you would be better off with 400 heads like the 1970 #13's I have a set on my 350 pontiac and they really woke it up a lot and they have bigger valves as well.