I own both a78 4dr buick lesabre with a 350 and a 4 barrel intake and a 71 buick skylark with a 350 as well but with the 2 barrel intake and carb....could i swap those two intake and carbs without any problem? I want to increase power on the skylark, or should i try and find a edelbrock performance intake and carb? , ,
The 78 4bb intake and carb will work fine on the 71 engine, easy swap and you will like the performance. Edelbrock does not make an intake for the Buick 350, however TA performance and Poston do however other than lighter weight the alum intakes are not much better than stock. Just so you know, hang onto that 78 engine since it has the stronger connecting rods compared to the 71.
Does that mean my 78 motor is more rugged and sturdy then my i woulda thought it was the other way around as engines got newer and is it true that 71's were built better then 72 smotors in skylarks? Still with the 2 bb my skylark is much faster and produces almost 60 70 more hp then the 4bb 78? Is it the way the motors were built because they are the same 350 block and i do know emissions got strick on cars as years went on.. And also how much of an hp gain will i aquire with the 78 4 bb setup?
In my opinion the later engines are more refined and better in all ways except lower compression. There is no doubt that the 73-80 engines have the better capscrew type connecting rods where as the 68-72 engines have the weaker rods that may break even under 400 hp. The 73 and later rods hold well over 550 hp, the old type will not for very long. Any Buick 350 will make power with the right tuning and combination, there is no bad 350 really. Both of your engines are low compression so not going to be much performance difference between them really if you tune them both up the same. The early heads are more prone to cracking, the later heads have a extra coolant passage to solve this. Some later heads have the 1.55 valves on the exhaust vs the 1.5 in the early heads.
hey sean, cant you use a 73+ heads on a 68-72 block...just have to block the extra passages? or does it only work the other way around
The 73-80 blocks can use any year head with no mods. The 68-72 blocks require the old heads because there is no support on the block for where the head gasket and center scallop are.
In 71 engines were rated in gross horse power (no accessories, water pump, etc), in 72 GM started rating engines in net horse power which is the main reason, besides the extra smog tuning and junk, that the 78 is rated 60 to 70 hp less than the 71.
so the 71 and 72 skylarks are pertty much the same in horsepower for is the 71 still going to be more if it was in net horsepower? and how much hp will i gain swapping my 2bb for my 4 bb into my skylark?
i would say around 20 hp ..maybe 30 with bigger then stock carb and good tuning on a stock application...obviously gains would be less if you have a mild buildup
So far nobody has remarked that porting the heads is one of the best paths to horsepower gain - along with dual exhaust. Don't have numbers to support that statement, but I've seen it expressed time and again. Can someone (Sean) chime in with their thoughts on this?
yea, gear swap would be most bang for the buck, and porting heads will do wonders also, then it's just the typical bolt on things anymore on the cars i upgrade, i start with the rear and go up
Well i do want to build my skylark up part by part it was completely bone stock until i added dual exhaust just straight back to x pipe or h pipe and kept the stock manifolds since bolts....i will be doing the carb swap and also get the 4 barrel rebuilt as well...anyone want to take a stab at a ballpark horsepower figure after the swap?....and i beleive my car is not posi either...
just duals and 4bbl swap?(go 750 or 800) i'd say real close to 200 rwhp yea, you most likely have a 2.56 rear...2.73 if lucky lol gear swap(3.08-3.42) would be the most bang for youre buck after you do the 4bbl swap...next would be a converter peferably by coan with something like a 2400-2800 range thant you can just save up and do the cam and all the head stuff like valves, cromoly pushrods, rocker arms or even roller rockers, and port work..
Ive been reading sites on the net showing 71 skylarks with the 2bb setup putting out 230 i guess gross hp and not net hp and a 4 bbl doing 250 or 260 or something like that somestimes ive even seen sites say as high as 285 im guessing thats not true....so my 71 bone stock produces just as much hp as my 78 without duals and the 4 bb setup ive checked the rating on my 78 350 and only seen it with 175 or 150 hp seems kind of slow im sure my skylark was pushing alot more then that bone stock with the 2bb and stock single exhaust.....
my setup was practicly like youres except i had cromoly pushrods/rocker shafts along with poston gs350-110 cam and headers and i'm sure i was only pushing out 240/250 rwhp...mines a 72 engine stock 4bbl that year was only 175 net hp 2bbl was 155hp net
The 71 & 72 2bll engines were identical I think, so the 230 gross hpof the 71 would be the same as 175 net hp of the 72. Probably the Skylark is lighter than the LaSaber which helps its performance.
This is very true, the best $ spent on a 350 is head porting in my opinion. You will need the re-jetting of the carb, headers, and re-curved ignition to take advantage of these things though. It is also important to get over 9:1 compression in my opinion unless adding a power adder.
i still say gears due to then youre only obligated to do posi in process.. when porting the heads you might as well do cam, and rest of valvetrain in the process so you dont have to reopen for just cam or just roller rockers etc
Hi everyone following up on this great thread! I just recently acquired a 72 skylark convertible 350-2bbl and was thinking about doing the 4bbl swap. Wondering if just the 2BBL and good tuning with exhaust and gears might be the way to go as well, dont wanna have to start changing to many internals as this will be a daily driver. Any input or experience is greatly appreciated!!
