350 head port & polish and cam swap

Discussion in 'Small Block Tech' started by EasyCompany7, Jun 14, 2013.

  1. alec296

    alec296 i need another buick

    Just slowed abit. To many projects. And family things. But I have the season pass so I'm trying to get the motorvation. Not sure if the convertible is going to make Norwalk so. Backup plan. And Carrie needs to make a pass to see if she can handle it.
  2. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    That's cool, thanks for replying, back at you.

  3. EasyCompany7

    EasyCompany7 Semper Fi

    Been over a year since I could make it back to the track. Made a few changes to the primary jets and rods during this time based on vacuum readings, exhaust note and spark plug loading. Settled on .072 and 45b, with a 15/32 float level, and a .149 seat. No changes to the secondaries.

    Swtiched from the cold air snorkel to a cold air feed from the grill, and installed a 1" wood/poly 4 hole spacer. Also been practicing launches in a nearby industrial street. Seems 3500 works best to avoid bog and let the clutch out within 1 second to avoid spin.

    GS cold air system installed 1.jpg

    Got to the Lapeer Dragway yesterday, was sunny and mid 80's, the track was hot. Ran the same ET's and mph as last year, mid 14's, 100mph. Good news is I didn't run any slower, but I thought it would pic up some MPH with the carb tuning and spacer, and I would chip away at my 2.5 second 60' with better launch technique.

    Was thinking that the tuning gains with the carb and spacer may have been negated by the long cold air set up. May try a big open 10" air cleaner for the track, seems most of the folks there don't run any air filter at all. Last year I was into 4th gear by the time I hit the traps, but this year I was going thru the traps at the top of third, at about 5200.

    Just a note, last year's temps were in the mid 70's, it was May, if that has anything to do with the results.

    Here's a pic of lining up during at the track......

    Lapeer Dragway lining up.jpg

    That Vega at the front left, was running 115mph 1/8ths and very close to 6 flat. See the tan, 4 door Ford (I think)...."run what ya brung"!! Was a lot of fun. I did beat three Camaro's head to head, one of them is in front of me in the pic. I think they were all 90's generation, running open headers, big scoops, wrinkle walls, and who knows what.

    I think about some of Larry "the Wizard" comments about how the track is intimidating, noisy, hot, and a totally different sensory experience from the street. For sure!! I get quite a nervous stomach the day before as I prep and the morning of. Once I get there and put the slicks on, eat something and hydrate, it's better. But unfortunately all my technique I taught myself during launch practice goes out the window at the lights: burnout, staging, ambers, rpm set, clutch release, it all happens so fast. But the adrenaline rush of banging thru the gears as the rpms climb is soooo worth it. Made seven passes, was so much fun.

    Any comments about the air cleaner set up are appreciated..........and I need to keep practicing my launches, the car would be in the 13's if the driver would learn how to drive a 4 speed!!!
  4. EasyCompany7

    EasyCompany7 Semper Fi

    Correction to my post directly above: The Camaro in the picture above is NOT one of the ones I beat head to head on Sunday. That Camaro is a sub-11 second car based on the timeslips. There were many Camaros there, several in white, I apologize for my confusion.
  5. DauntlessSB92

    DauntlessSB92 Addicted to Buick

    As far as the air intake setup, there will always be differing opinions on what makes the most power. Some say you need the coldest air possible, others say the shortest run possible to keep velocity up.

    Of course the best of both worlds would be optimal. Without cutting a hole in your hood and sticking a filter through it, I think your best bet is to do a K&N air cleaner with the top filter element. The more surface area you have the better the filter should flow. No air filter would make more power but I don't feel that the extra mph or so is worth the potential engine wear or damage.

    Of course you know all the time you need to make up is in your 60ft. You probably have .6 that can be taken off with a clean launch on slicks or drs. That would work out to almost 1 second or more in the quarter.

    I can't offer advice on the launch being that I have an automatic. Took my focus st to the track once and I was so terrified of either roasting the clutch or breaking an axle that I never got the launch right.
  6. UNDERDOG350

    UNDERDOG350 350 Buick purestock racer

    I'll bet that 90 hat on top of the carb is causing a major air distribution issue. Too close to the crab top. Those are generally used for blow thru carb/boosted applications. Very easy to find out. Make some runs with it then swap to a round 14x3 filter. You are tuning with an air/fuel meter correct? Ditch the carb spacer also.
  7. EasyCompany7

    EasyCompany7 Semper Fi

    Thanks Jacob and Steve for your help. Like you said, will be easy to test the difference between the cold air kit and the open 14" at the track. I tried the 1" spacer because I saw these results posted here some time ago (I highlighted the results of without and with a 4 hole spacer in red):

    We found the T/A stg.1 gave us about 8 cfm increase in airflow with stock heads and manifold. About 18 hp.
    With headers alone it picked up another 6 cfm and 12 more ponies.
    Now throw a ported set of heads with the bigger valves in the mix and the manifold really kicks up the numbers. This is without modifying the manifold, using a 800 Qjet, and the stock cam. About 48 hp.
    Bill M.
    Too many to list since '66
    72 GS 350

    Well I finally got my engine on the dyno today!!! Special thanks to Jim Wiese for building my engine!!!!

    Engine specs: 1972 350 bored 30 over, T/A 10.25 pistons, (actual compressin is 10.12), Poston GS112 cam, headers, stock valves with pocket porting and bowl cut back with performance valve job, stock rebuilt 750 quadrajet, hei ignition with an MSD 6 box.

    I also want to thank GSCALIFORNIA for lending me his T/A intake for my testing!!!
    I started out with the T/A, set timing at 35 degrees all in by 3,000rpm's. First run was Peak HP was 365 at 5,500rpm, torque was 393 at 4,300rpm's, hp avg 322, torque avg 373 between 3,400-5,700 rpm's.
    Not bad for first run!!! fuel ratio is 10.91-14.05, avg 12.43!

    Now I put on a 4 hole 1 "spacer and here it is: Peak hp is 371, avg 325.
    Torque peak is 398
    , avg 376!
    Now I switch to an open 1" spacer, I lost 40 lbs of torque at 3,800 rpm's, 391 vs 341!!!! Avg hp is 321, avg torque 372.
    It did not like the open spacer!

    Now I swap to the cast iron intake with the four hole spacer.
    My torque comes in earlier, nice, more bottom end!!
    At 3,400 rpm's I have 370 lbs of torque vs 360lbs with the T/A! And 239 hp iron vs 233hp T/A!
    At 4,000rpm the iron is 300 hp and 394lbs torque vs 303hp and 398lbs torque!
    At 5000rpm's iron is 355hp and 373lbs torque vs T/A 351hp and 369lbs torque!
    Peak hp and torque in the iron 368hp and 395lbs torque, avg 322hp and 374lbs torque.
    T/A peak 371hp, 398lbs torque, avg 325hp and 376lbs torque!
    So there you have it!!!
    T/A intake $290.00 for an avg gain of 3hp and 2lbs of torque across 3,300-5,700 rpm's!
    Not a bargain, I will save my money and keep the iron!
    I only wish I could get my hands on a single plane high rise intake!!!!

    Of course, I could try with and without the spacer at the track, just would take a little time under a shade tree, waiting for a hot motor to cool off some.

    For the carb tuning I was using the old school method of inches of vacuum, sound of the exhaust pulse, and carbon on the spark plugs. Just looked up the price of a dual air/fuel meter, $400-$500 not including welding, yikes, might have to put that on my Christmas list.
  8. 300sbb_overkill

    300sbb_overkill WWG1WGA. MAGA

    Tuffy in Rochester can weld the bungs on for you for $50 both sides.

    I paid $396.88 shipped for my Fast dual O2 wide band A/F ratio meter from Atlantic Speed from eBay.

    Here's a used one for almost $100 less that looks like a good deal;


    If you don't mind buying used. A lot of people will buy one and use it once and it will sit there and eventually end up on eBay because they either don't need it anymore because they sold their old car or they dialed it in and don't need to mess with it anymore? If you only need it once and your done a used would be a good way to go. If you are going to be swapping carbs to see if that makes a difference and keep needing one a good used one is still a good deal. The $$ you save you can buy the data logger ad on or you'll need someone reading the gage while you drive. GL

  9. Dan Jones

    Dan Jones Well-Known Member

    > Poston GS112 cam

    I did a quick search on that cam and came up with the following specs:

    288/300 seat duration, 0.510"/0.518", 112 LSA

    Does anyone have the durations at 0.050". We just rebuilt and dyno tested a Ford 351C that had very similar peak torque and power (378 HP @ 5700 RPM and 396 ft-lbs @ 4100 RPM) and I'd like to compare the builds (in Dynomation).

    Dan Jones
  10. DauntlessSB92

    DauntlessSB92 Addicted to Buick

    I'm a believer that the 4 hole is a benefit on the dual plane intakes. I ran a 1" 4 hole spacer so I could use the TV arm for my 2004-r. Between that and switching to the 800cfm q jet over the 600cfm holley, it was night and day
  11. EasyCompany7

    EasyCompany7 Semper Fi

    Went to the Lapeer dragway in June to test several different air cleaner intakes, assemblies and spacers. During the third pass I could really feel the clutch slipping and on the return lane there was a lot of grinding from the tranny. Got back to my pit area and I couldn't get the tranny out of gear.

    I let it cool for an hour, it would then shift, drove it in the pit area and it would shift all four gears, and the noise was gone.

    So, we decided to head home, about two miles from the track the tranny locked up and we called for a flatbed tow.

    The tranny has been rebuilt, and now waiting for the flywheel to be machined and a new clutch.

    Was a nice day there though, met a couple of Buick guys and Olds guy, attached is the pic of their cars.


    Attached Files:

  12. EasyCompany7

    EasyCompany7 Semper Fi

    Ya, living in da UP now, eh..............Moved up here last summer. The GS is driving good, in the garage for the winter.

    Any other Buick owners living here near Newberry, MI??
  13. Stevem

    Stevem Well-Known Member

    If your grinding your Intake ports with both a ruff fast cut Burr and then a fine cut Burr there should be no need to polish the port , in fact it makes for the fuel to cling to the walls in balls that are much harder to light off once they make way into the chamber.

    in regards to testing if a chain replacement is needed it goes like this.
    If will all the spark plugs out your rock the Crank back and forth and the Distributor rotor does not follow right along, then it's time!
    aways install a 2 degree advance key to make up for normal chain stretch when running even with new parts!

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