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Pontiac Staight 8

Discussion in 'The Hokey Ass Message Board' started by Brizo, Oct 8, 2011.

  1. Brizo
    Joined: Jan 15, 2011
    Posts: 222

    Brizo
    Member
    from Indy

    I saw an old post about a guy trying to find speed parts for Pontiac 8's. As he was told, Edmunds did make a finned aluminum head but they are very rare today, especialy in good condition. These engines can be made to run much better than stock and still be dependable as ever. Her are a few shots of my 268 in. engine in my '41 Pontiac. adapted to a Muncie 4 speed and 3:63 diff. It has dual Holley-Weber carbs, HEI. Crane cam, .080 milled head, dual bank headers and pipes.
     

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    bob vota and J.C. Andersson like this.
  2. superchargedill
    Joined: Apr 5, 2010
    Posts: 226

    superchargedill
    Member

    Very Nice. Glad to see you have a real Pontiac engine in your Pontiac
     
  3. captainjunk#2
    Joined: Mar 13, 2008
    Posts: 4,420

    captainjunk#2
    Member

    thats a beautiful engine , nice machine
     
  4. Nice to see the original engine and a remarkably pretty specimen at that. Where did you get the manifolds?
     

  5. Ole don
    Joined: Dec 16, 2005
    Posts: 2,915

    Ole don
    Member

    Really cool engine in a very nice car.
     
  6. JackdaRabbit
    Joined: Jul 15, 2008
    Posts: 498

    JackdaRabbit
    Member
    from WNC

    Real sweet car. Congratulations on building the straight 8. So much more expensive and difficult than stabbing in a SBC or even a Poncho 400. Kudos on the force-feed trans, too!
    Steelies and Sombreros would make it absolute Tits ......for my taste that is.
     
  7. Brizo
    Joined: Jan 15, 2011
    Posts: 222

    Brizo
    Member
    from Indy

    Thanks Guys! I made the water heated plenums, and finnished and painted them to look like cast aluminum. Adding the Muncie to the original belhousing was easy, mostly just enlarge the center hole to match the Muncie clutch bearing support. The upper bolt holes even match up.
     
  8. oldiron73
    Joined: May 26, 2009
    Posts: 400

    oldiron73
    Member
    from WISCONSIN

    Does it get up and go pretty good with the dual setup and 4spd.......
     
  9. Brizo
    Joined: Jan 15, 2011
    Posts: 222

    Brizo
    Member
    from Indy

    All I can say is, its a lot faster than stock. It does no good to open the secondaries below 3,000 rpm, Based on formulas I've found on the net, this engine (268ci.) can only pump about 300 cfm. Flat heads just dont flow air as well as OHV engines. The biggest mistake guys make in "souping up" vintage engines is over carburetion. Some famous engine builder once said," the most modfied flat head still cant breath as well as the worst OHV"
     
  10. Brizo
    Joined: Jan 15, 2011
    Posts: 222

    Brizo
    Member
    from Indy

    I can say for sure about me '41 -the cam, headers, etc. really start to work together around 2,800 rpm and it will go from 60 to 80 mph. in 5 seconds. Compare that to a stock Pontiac 8 sometime.
     
  11. Normbc9
    Joined: Apr 20, 2011
    Posts: 1,121

    Normbc9
    Member

    Beautiful car and I like what you did to the Straight Eight. They had power, torque and were extremely dependable. You had a chore to find the parts, I'll bet. Be proud. One of a kind now. The old Buick's, Oldsmobile's and Pontiac's were all got motorcars.
    Normbc9
     
  12. Greg in Jax
    Joined: Jun 27, 2010
    Posts: 209

    Greg in Jax
    Member

    Beautiful car, beautiful engine. Thanks for posting the photos. I am running an Edmunds intake with two Stromberg 48s and a Pontiac high compression head milled .080 on my 268. I had no luck finding info on a cam so it is still stock, and I would be really interested in the specs of your Crane cam if you would not mind posting them. Thanks again for the post! Greg
     
  13. outlaw256
    Joined: Jun 26, 2008
    Posts: 2,022

    outlaw256
    Member

    like what youve done with the st.8.looks really good.ive got one sittin in the floor that i was gonna put in something but i dont have the time anymore. know anyone that might be interested in one?.yours is kinda what i had in mind for this one,but things didnt work out the way i wanted.so now im gonna sell it or trade it off.
     
  14. Andamo
    Joined: Jan 10, 2006
    Posts: 523

    Andamo
    Member

    I have to say there's something real righteous about what you've done. You could have done what the masses would have done and went with a 350/350 and bored the livin' snot outta us. But to use a Pontiac straight 8, along with a 4 speed makes me smile. Even if it doesn't rip up the pavement, you deserve a huge Attaboy for keeping the innovation in hot rodding. Thanks.
     
  15. Adrian Rollini
    Joined: Aug 30, 2011
    Posts: 155

    Adrian Rollini
    Member

    Thats a great looking motor. Straight 8 motors are solid engines. I always wanted to have one. I was going to buy a 52 Hudson Hornet 7 years ago with a staight 8 motor, but I settled for a 50 chevy with a 235.
     
  16. bad ass car and motor.
     
  17. Brizo
    Joined: Jan 15, 2011
    Posts: 222

    Brizo
    Member
    from Indy

    Thanx Guys! GreginJaX, The cam was reground years ago by Crane . The The grind was called "Hi-Torque Track and Drag 350" used in the '50s and probably considered a "3/4 race" in the day. 350 was the lift and the duration was 252. specs were intake from 18 BTDC to 54 ABDC, and exhaust was 56 BBDC to 16ATDC...basicly the increased the lift .050 and the duration approx. 40 degrees. It has a nice gurgle at idle(800 rpm) and everone thinks its a V8 when they hear it. I located 2 of the very rare Edmunds finned Pontiac heads 2 years ago which I would love to have,but only one was for sale and the price was outrageous!!! and they wouldnt send me photos or say anything about the condition.... maybe someday I'll get one. There is a pic of one on Inliners International
     
  18. Greg in Jax
    Joined: Jun 27, 2010
    Posts: 209

    Greg in Jax
    Member

    Brizo, thanks for your reply. I have a spare cam, so perhaps I can find someone to grind it - thanks for the specs. Best wishes, and keep me in mind if you find two of those heads again. Greg
     
  19. bob vota
    Joined: Jul 5, 2014
    Posts: 2

    bob vota

    Hello interested in the performance parts you have on your engine .. were did you get them or did you make make them .. I'm doing a 49 Pontiac .. I have a 51 block and high compression head could use all the info I can get ..
     
  20. Hudson Hornets had 6 cylinder engines
     
  21. dirty old man
    Joined: Feb 2, 2008
    Posts: 8,910

    dirty old man
    Member Emeritus

    About all I know about Pontiac straight 8s is that the GA State Patrol used them in preference to the Ford "Police Interceptor" flat heads which were really Merc engines with the 4 inch crank. They were wicked fast on top end for that time.
     
  22. J.C. Andersson
    Joined: Jul 7, 2013
    Posts: 35

    J.C. Andersson
    Member

    Brizo, I would like to get a manual three-speed Chevy trans with overdrive on my 1947 Poncho with a 1953 engine. I am very interested in some details on how you got the Muncie in place on the bellhousing. An adapter plate? And can the original clutch be used? I suppose you have a floor shifter now, But I will try to adapt the column shifter somehow.
    J.C.
     
  23. Bruce Lancaster
    Joined: Oct 9, 2001
    Posts: 21,681

    Bruce Lancaster
    Member Emeritus

    Hmmm...back about 1950 or 1951, the great tech guru Don Francisco did a tech and hop-up article on a different engine in each issue of Hot Rod. He covered a bunch of oddball ones, and I think he covered the Pontiac 8.
     
    J.C. Andersson likes this.
  24. RichFox
    Joined: Dec 3, 2006
    Posts: 10,020

    RichFox
    Member Emeritus

    He just told you that he had to bore the center hole larger to fit the later transmission. I don't know how much, but you could measure yours to find out. You may be able to turn the OD of the bearing retainer to fit your bellhousing. The top two holes, he says, were already correctly located. So I guess that means he had to drill and tap new lower holes to match the trans. A clutch disk that has matching splines to the trans input shaft will need to be used. The diameter will need to match your original part to use your clutch cover. Brizo didn't say anything about the pilot bearing so I guess they are the same size. Or you might have to make one out of oilight bronze. That's what I get from reading his post and having done similar adaptions myself. You do need to be able to think things through, but it's not hard n you decide to do it.
     
  25. 302GMC
    Joined: Dec 15, 2005
    Posts: 7,856

    302GMC
    Member
    from Idaho

    A friend is going with a '57 Chev OD into a 6 cyl. '48. Looks like he'll use the Pontiac sleeve & release bearing ass'y, keeping factory clutch linkage ... the cable selector shift linkage will be replaced with either '49-'52 or '53-'54 Chev shift linkage, depending on the mast jacket diameter.
     
    J.C. Andersson likes this.
  26. J.C. Andersson
    Joined: Jul 7, 2013
    Posts: 35

    J.C. Andersson
    Member

    That sounds more or less just like my idea of how it could be done.

    Richfox, the two lower bolts will be placed below the edge of the bellhousing, hence my question about an adapter plate. No metal there to drill and tap.
     
  27. RichFox
    Joined: Dec 3, 2006
    Posts: 10,020

    RichFox
    Member Emeritus

    Maybe you could drill new holes in the transmission ears. I have done that on a Ford top loader. Otherwise I wish 302 would let us know what he did.
     
    J.C. Andersson likes this.
  28. J.C. Andersson
    Joined: Jul 7, 2013
    Posts: 35

    J.C. Andersson
    Member

    It's been done before, so I will look on different solutions. Too bad there wasn't an overdrive offered from Pontiac at the time. A friend of mine "mated" a R10-unit to the syncro-mesh. That included welding, tedious machine work, a propane heater, a freezer and if I remember right, eleven balls from a big bearing. o_O I still think it must be easier to make a complete set fit to the bellhousing, with or without an adapter... So I hope Brizo or 302 can enlighten me a bit. Brizo, I really like your car by the way, and I'm sorry that I take advantage of your thread! I hope it's ok.
     

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  29. 56sedandelivery
    Joined: Nov 21, 2006
    Posts: 6,695

    56sedandelivery
    Member Emeritus

    Absolutely beautiful car! So............how much time did your header builder actually spend in the mental institution? I'll bet those headers took some planning. I am Butch/56sedandelivery.
     

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