Hi Rob. The thing I would do is find a 350 and work it over. Put it on a stand and tear into it. Be happy with the 300 for now, it's a great little engine. Spend this Summer gathering pieces for it so the Finance dept. doesn't get too upset. Maybe drop it in next Winter or whenever it's possible for You. If you have any questions get it touch with Sean, he's a great source for info. That's about it tho. :laugh: Sorry Sean, I HAD to. I like my 350 and when ported with a nice cam it'll Run!! What kind of Trans are you running? PONCH
rob : FYI - you mentioned headers and at this point in time i do not think there are any "old school not too expensive easy drop in" style 350 headers for the 64-67 body style . 68-72 style , right side frame clearance ok but left side hits big time . down the road - maybe . custom built - probably .
The choice to go with the port arrangement is unknown but I am sure it had nothing to do with performance or flow capability. Well for one the GN heads flow very little, but the turbocharger makes the engine output respectable. From what I have read the GN heads only flow 156 CFM intake and 110 CFM exhaust @ .500. I do not have the baseline non ported numbers for the 300 heads but here are professionally ported ($2000) versions of the 300 iron and alum versions. I can only imagine how poor they flow before $2000 in work. Alum heads flow test: And the flow test for the iron 300 heads: The 350 heads gain about 50 CFM stock over the GN V6 heads: Stock Flow, stock valve... intake .050 - 27 .100 - 55 .200 - 112 .300 - 165 .400 - 199 .500 - 196 .600 - 199 exhaust .050 - 22 .100 - 44 .200 - 87 .300 - 119 .400 - 137 .500 - 146 .600 - 149 Ported, 1.92/1.55 valves Intake .050 - 32 .100 - 60 .200 - 116 .300 - 172 .400 - 215 .500 - 247 .600 - 262 exhaust .050 - 27 .100 - 53 .200 - 102 .300 - 145 .400 - 175 .500 - 177 .600 - 182
Yeah,the later boat anchor sbb 350 heads flow more unported than the expensive ported 300 heads. But the TA rover head will work on a 300/340 and can be made to flow quite well according to the TA catalog.:eek2: Derek
Derek, It would be nice to put a set of Rover Aluminum Heads on a 340. The exhaust Manifolds flow very well. I ported mine out to match the heads. The 350 Exhaust Manifolds are just a big box with holes. I wouldn't go .05 over on a 340. It would keep me wondering when is this gonna blow into a water jacket. Also, the GN engine was based on a 350, not a 300/340. Those Two engines were long gone before they started working over a V6. I've always wondered why they didn't make the 4.1 V6 into a viable package with the Turbo. No replacement for Displacement. I sure did love doing my own road tests with them while I was working there. PONCH
.050" over would be no problem if it passed a sonic test,I wouldn't just bore it .050" without making sure it could handle it.The 340 block might be thicker than a 350 if they weren't as worried about weight savings in 66 and 67 as they were for the new 68 350?(not sure,sonic testing would tell the tale though) Derek
What part of a GN engine resembles a 350? I've had 225s, 300s, 340s and a GN and I've rebuilt them all, they're all the same engine. The 231 has the stroke and port arrangement of a 300. The only reason the went from 225 to 231 is so the could use the350 pistons for economics reasons. The 225, 300, 340 and 231 and all siblings, the 350 is a cousin at best.
The 350 is the only engine in the "Family" with a 3.8" bore. The same as a 231 V6. I put 10:1 V6 Pistons in my 350 and they work fine. I shift at 6000 if I want to Haul Ass. You cant have the Same port arrangement on a V6 and a V8. With Two extra cylinders, it makes a lot of difference. Read up on both the 350 and 231 and you'll find the 350 is the Big Brother to the 231. it's a 350 with Two Cylinders cut off. I spent a lot of time in the Enginering factory at "The Buick" in Flint and know what I'm talking about. PONCH
ok . i know the motor mount part of the block is same and measurement to bellhousing same but from there up the 300 and v6 look more narrow ( angle) than the 350 . maybe its just the head exhaust port exit angle that throws me off . edit : ok - I was thinking of maybe an older narrow lookin chevy 60 degree v6 ?
All Buick V engines are 90*. The 231, 215, & 300 are narrower but that is because they have a lower deck height.
I've never seen a V6 Buick with exhaust ports right next to each other (like a Chebby or a 350 Buick). Ray Charles could see that! Yes, when they brought the V6 back they bored it .050 so they could use the 350 pistons for economic reasons. The bore is the same as a 350, otherwise it's a V6 version of the 300.
Anyway, to get back to what started this thread, if it were my car I would go with HEI (which I believe he has already done), put a curve kit in the dist and duel exhaust (if it doesn't already have it) and leave it alone unless he's trying to set a new land speed record. I wouldn't waste time or money putting a TH350 trans in it since the switch pitch TH300 is a better trans. The only reason they went from the TH300 to the TH350 was cost, it's cheaper the put the extra gear in than the switch pitch. A 200R4 would be nice but then he would need to change rear to a 3.23 or 3.42 but it may be worth it, but then the power valve in the carb would need to be changed to open at 7 in hg to get the full advantage in MPG. To go from a 300 to a 350 would add 10% hp and subtract 20% in fuel mileage, not worth it in my opinion. I like to drive my cars. I have two 65 Specials, both with 300s, one is a 4 speed (conv) the other an auto (post coupe), and I barely touch the gas pedal in normal driving. The 4 speed car will bury the speedometer and the auto tops out at 110. My 65 Skylark is a 225 V6 with 200R4 and a 3.23 rear and it has enough power to break every speed limit on this continent and cruises 85 all day long. What is it that your guys are trying to accomplish? We did all that horsepower stuff back in the 60s!
If he was happy with the power from the 300 then he would not have started this thread... It is great that you are happy with your little engines, they do run great.
