1967 skylark radiator size?(27.5x18.5) Thanks Guys!

Discussion in 'Street/strip 400/430/455' started by nickthehick78, Jun 1, 2019.

  1. nickthehick78

    nickthehick78 Active Member

    to cut to the chase....
    my questions are.....
    what s the biggest core size that will fit in my 67 skylark?
    did the 67 gs have a bigger radiator?
    whats the biggest size radiator people on here run and how much modifying did it take to fit a bigger one?

    i have a 67 skylark i put a 70 455 in years ago. it is in Connecticut and i moved to Texas 2 years ago, im ready to go get my Buick finally, but before i road trip it 2000 miles i need to fix a few things. one thing was i had a slightly leaking radiator before i parked it and need to replace for the Texas heat. it is a factory ac car and all ac works properly and i use it unless its too hot out and engine temps climb.

    so the car is 2000 miles away so i can not measure anything. i want to order a radiator and have shipped to the car so i can fly home, install it and drive to Texas.

    a few years ago i was running a ta performance high flow water pump and it dropped temps 20 degrees. ive changed it to stock since then but had it on when i tried the aluminum radiator im talking about below. ive been running a 180 degree, robert shaw style thermostat the whole time.

    then i got a 1" tube, duel row aluminum radiator with shroud and electric fan. it was a direct replacement, for my factory size radiator that came out of it, i had to order a different radiator. i believe it was for a 67 nova. a 26" core. it dropped in and worked great at idle and in traffic, but at highway speed temp would climb. i tried adjusting carb, timing, nothing helped. everything pointed to too small of a cooling system, or to fast of coolant flow with the high flow water pump and 1" tube radiator. i remember thinking a double or triple pass radiator might fix it. or a stock flow water pump. i ended up pulling it and putting the old 3 row leaking radiator back in and have run it for years with no issue other than needing to add coolant every few weeks.

    i remember when i ordered the radiator, and now in my searching, every single company said 67 skylark has a 33" core, well my dad has a 68 chevelle we did a whole cooling upgrade to it and i remember trying to fit his 33" core in my Buick and it wouldn't even kinda fit. think i remember it hitting frame rails as the worst part, being covered by sheet metal on core support, and just would not work at all without serious cutting.

    i would love to be able to fit a 33" core in my buick, it would really help. but i need to know what size to order for my car.

    so my questions are.....
    what s the biggest core size that will fit in my 67 skylark?
    did the 67 gs have a bigger radiator?
    whats the biggest size radiator people on here run and how much modifying did it take to fit a bigger one?
  2. DauntlessSB92

    DauntlessSB92 Addicted to Buick

    Have you considered having your original rebuilt with a 4 row core? I am going that route myself with my 67 GS400 and should have the radiator this week.
  3. nickthehick78

    nickthehick78 Active Member

    Yes. I thought of that, but I wont have the time. I'm planning on flying one way to Connecticut, having a few days to get the car ready and driving it back. No time to pull and get recorded and install.
    I also feel like I should be able to get a good new aluminum radiator for cheaper than a record.
  4. Quick Buick

    Quick Buick Arlington Wa

    My 3&4 Core Rads are the same square dimensions....without removing from car...... but the 4 core is tank is 3 1/8'' while the 3 core is 2 1/2'' thick
  5. nickthehick78

    nickthehick78 Active Member

    But what width is the core and is yours a 67? I find 67 always is the oddball for parts. And think the radiator is all same length at 18 1/2" or something like that.....but mine has a 26 or 28" now and all web sights call out a 33"
  6. Quick Buick

    Quick Buick Arlington Wa

    4 core 2 3/4''. 3 core IDK. not at the car.
  7. Quick Buick

    Quick Buick Arlington Wa

    pm sent
  8. BuickV8Mike

    BuickV8Mike SD Buick Fan

    18 1/2 is the height.
  9. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    I can't imagine why a dual core aluminum radiator with 1" tubes would not cool your engine. Did you try it with a regular clutch fan? I'm not a fan of electric fans except on late model cars. On the highway, I bet they actually restrict airflow even when running.
  10. wkillgs

    wkillgs Gold Level Contributor

    That's what I'm using in my 66 GS. Worked fine on the few 100 degree days I had it out.
    You can get larger tubes, 1.25" and 1.5" for more capacity. They're still only 2 rows tho. Iirc, The aluminum tubes are stronger than the old copper style, they can make them larger, and can use 2 rows of large tubes vs 3 or 4 rows of the smaller copper tubes.

    Max width is about 27.5" for the 1964-67. I think it was Olds that had the front frame horns which splayed out and used the wider 33" radiator.

    Here's a Griffin with the 1" tubes. Large tube models are avail.
  11. BuickV8Mike

    BuickV8Mike SD Buick Fan

    How clean is the system. Took the proper timing and 4 or 5 flushes of the system before mine would cool properly (the flush was finally clean). Ran 100% distilled water for a week at a time and then drained and refilled. The first few times were filled with rust particulates.
  12. nickthehick78

    nickthehick78 Active Member

    responded....thanks for taking time to message me!
  13. nickthehick78

    nickthehick78 Active Member

    great. thanks! i thought it was around 18"
  14. nickthehick78

    nickthehick78 Active Member

    i cant remember but i dont think i did try with mechanical fan. i had the stock shroud for the 340 small block but when i went 455 it did not fit and i cant find a gs or big block shroud so i still have to make one. i patched it with a 6.2 diesel fan clutch that runs at something like 80% over the 30% or so the stock one did. its loud and robs power but got me by in connecticut, but i dont think it will work in the texas heat.

    i think it was you who did the "power timing" page on here. it worked wonders on my car....and im pretty sure you were helping me on a thread i started when i had the cooling issues and did the radiator swap....it must have been 3-4 years ago at least.

    everyone on that thread concluded too small of a cooling system (but it was about the same size as before that worked), or it was a air stalling under hood (alot of people have 455s in 67s and dont have an issue), or it was a too fast of flow through the system and needs restriction where thermostate goes, or low press waterpump with that radiator, or a triple pass radiator with that hi flow water pump (again, all patches and people are running normal parts on their 67s just fine)

    now i do drive fast and am fine on the highway at 65 mph, i was running hot over 75 sustained and up. but i have a 3.55 gear and a 25-26" tire, and was holding it at around 3800 rpm at those speeds if i remember correct. i know i will need a gear vendor or regear to drive in texas.
    Last edited: Jun 2, 2019
  15. nickthehick78

    nickthehick78 Active Member

    AWESOME! the 27.5 is the number ive been looking for this whole time. i knew it was something like that and was 99%sure a 33 would never fit without hacking my frame.
    thank you so much!
  16. nickthehick78

    nickthehick78 Active Member

    its too clean. hahaha. that was part of my chasing cooling issues. timing then coolant flush....when i flushed it was brown and nasty. i was told to use dry cascade dish washer soap. i put it in and ran it then drained it. it cam out nasty. but worked great.....so i over did it and poured it in and could hear it sandblasting the high flow waterpump while running. it was crazy. i did this maybe 4 times. got it to run almost spotless and tons of rust and scales came pouring out as i drained each time, this is intoxicating to a neat freak like me. so keep doing it till its spotless!!! hahaha . drove it and it dropped temps like crazy! it was one of the best coolant fixes i did......then checked and saw a little brown in the coolant.....i cant have that and it worked great, so i threw some more stuff in it and instead of draining it ill drive it around, that will really circulate and clean it.....the sound of sand blasting went away. i drained and was good for months.......months later, heading out on a date. got half way to the girls house, temp climbs, smoke, coolant leak. out water pump. get water and limp it back home. pull my expensive TA performance aluminum high flow water pump, and it looked sand blasted, and went so thin on the wall the pressure hits, it wore a pin hole in the housing!!!!! so it worked great, but i wouldn't recommend doing it my way, or maybe use a different cleaner. hahaha
    Bills72stage1 and BuickV8Mike like this.
  17. nickthehick78

    nickthehick78 Active Member

    i ordered a champion radiator , 4 core, 21" core. it was a direct replacement for my original , leaking 4 core i had in it.
    i flew home for Christmas and threw a battery in the car and it fired right up and ran perfect after sitting 3 years. flushed coolant and replaced radiator. changed all fluids and fixed some brake lines and cleaned rats nests.
    got it going good and road tripped it 1800 miles to texas from connecticut! ran great. only issue was some guy cut me off bad, may have hit my bumper, small scuff, in nyc. i jacked my brakes and all 4 tires locked up. few miles cab filled with smoke, my driver rear brake was dragging. i hit the park brake a few times and it freed up and no more issues. other than that it was perfect, coolant was at 180-190 the whole trip. never went up. car was perfect.

    drove just under 1800 miles
    got around 11 mpg
    burned 177 gallons of gas
    cost $447 in gas

    now i got it registered in Texas, just waiting on my classic car plates. cooling perfect but really worried with how hot it gets here in the summer and running ac, so i went to summit racing right down the road(i love having a summit i can drive to) and got a derale power pack, duel fan shroud. its the smallest they make with duel fans. im going to have to modify it to fit, just a freckle too big. ill update when done.

    thanks for all the measurements everyone. it helped me out being so far from my car.
  18. 94IDI

    94IDI Jared

    Subscribed. Thanks for all of the info here gents!
    nickthehick78 likes this.
  19. nickthehick78

    nickthehick78 Active Member

    i got the electric duel fan shroud to fit my tiny 21" core! a little modification but it fits and is sealed tight. can pull in, and hold a wet rag against the ac condenser just sitting at idle....should be enough air flow. they advertise it for 3750 cfm. only issues im having is tuning the derele pwm fan controller. reading online, tons of people have issues with it. it sounds great with the soft start and pulse width modulation, and works sometimes, but still figuring out how to properly set it. it is great that the fans run slow, at idle and not that hot out i hit 180 and couldnt figure out why fans dont work, start checking wires, checked fans and they were on! keeping it at 180 and running 60% you cant hear them at all!

    anyways, i test drove it last night, i swear its like i sold my old car and got a new $30,000 car. WHAT A DIFFRENCE! it runs soooo smooth and quiet now. my ears felt like they had to pop because im use to it being so loud in there that it felt like something was wrong with my hearing. my old fan was super loud. (i ran a 6.5 diesel fan clutch and 7 blade fan to make up for the lack of a shroud). temp never hit 200. all i can hear is exhaust and i can even hear the intake sucking air, ive never heard that! feels like a new car! it had to of freed up some hp too, revs way faster and i was going 45 mph and punched it and it came out sideways, never did that before! love it. 100% recommend it...for now. lets see how she does in the texas heat and traffic this summer.
    68Rivi_In_Cali likes this.

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