Jump to content
Forums Gone... but not forgotten!
Pontiac of the Month

JAH11's 1968 GTO

2024 June
of the Month

  • Rev up your passion for Pontiacs and join our vibrant community of enthusiasts!

    Whether you're a die-hard fan of classic muscle cars or you've got a soft spot for sleek modern models, you've found your home here at Forever Pontiac. Our community is dedicated to celebrating everything Pontiac, from the iconic GTO to the legendary Firebird and everything in between.

    Unlock access to expert advice, stunning photo galleries, engaging discussions, exclusive events, and more!

    Start your Pontiac journey with us today!

    Sign up now! 🏁

'61 Bonneville progress update

Recommended Posts

Hey there @Frosty @JUSTA6@64 kiwi boni@Fitzy@Wrongway

Sorry it's been a while since my last post, but I've been kinda busy & the car is grounded anyway.

The final diagnosis on the random tuning issues was...it shit itself, thank fully in my own garage🤨

I think I'd posted I had been chasing issues with apparent hesitation/breaking down under load. I'd done everything I could tuning wise (replaced all the usual offenders, adjusted dwell, timing, etc, set AFB mixtures as best I could. Car would start first time, idle like a dream, but as you opened the throttle it would carry on a treat.

I finally gave up & booked it in with my mechanic to give it a thorough going over, as I suspected either the electric fuel pump or further carby issues. Scratching my head I started it one more time & an awful mechanical rattle began🙄

Since then we've discovered it appears to have had a Mexican rebuild at some time prior to being imported (2013), & whoever built it should really not give up their day job as a @#$%ing butcher!

They had fitted some kind of dodgy helper spring on the inlet valves, behind the valve head on the combustion chamber side. They really weren't even seated firmly, just seem to have been moving around in there doing #$% all, when one finally let go completely, destroying a piston, but thankfully not a lot else (other than a scratch in #6 bore & a bent rod). Also most probably causing the preignition problems that I didn't realise I had🤷‍♂️

After having it completely stripped and checked, it seems the '59 block (produced November '58) isn't in too bad a condition, but has already been bored .030". The crank is quite good & will be machined, but almost all other consumables aren't much good. Cam stuffed too.

So...it is being rebuilt .060" over - most parts (ex-US) accessible, but finding valve train gear for the '60 heads has proven almost impossible. Waiting on an answer from the (very experienced) machinist on whether we will be able to simply sleeve the guides & re-use what we have, as the costs are building & there are limits to my budget😬

If anyone happens to have a set of old stock new valves, retainers & springs (Valve length 5.3175", angle 20 degrees, head casting #536109 (1960), B170, X2 freeze plugs) they are willing to part with that would be awesome, although I'm not holding out too much hope. Chuck at Butler Performance even wished us luck, but was happy to provide all of the part numbers for what we need.

Enough for now, don't want to bore you all.

I guess this could have gone in the Performance Discussion Forum, as anything I do from right now will increase it's performance🤣

Edited by Bonne61
  • Sad 2
Link to comment
Share on other sites

Tired of these Ads? Register Today!

  • 2 weeks later...
  • 1 month later...
  • 1 month later...
3 minutes ago, JUSTA6 said:

What a find!!!  Can't help but sit here N stare.


3 minutes ago, JUSTA6 said:

What a find!!!  Can't help but sit here N stare.

Hehe, we've actually owned her since September last, but it's been in for an engine rebuild since January.
A long wait, but an awesome outcome. Original 389 (.060" over, now a little over 400ci) with a "mild" cam, shaved heads & block, & Butler forged pistons (to name but a few bits).

Love that sound 😄

  • Like 2
Link to comment
Share on other sites

3 hours ago, Wrongway said:

Damn it Paul, now thats clean bro. Super impressive. :cheers:

Thank you 🙏🏼 

3 hours ago, JUSTA6 said:

Brand new 61. WOW

Thanks mate 😀

  • Like 1
Link to comment
Share on other sites

We were originally going to install a Holley as part of the build (my builder has a lot of history with them through building cars for drags & racing), but what with some research & advice opted to remain with the Carter (it's a 4242s from a '67 Firebird, not the original 2820s).

Current economy (after about 400 miles over the last 5 days) is a little under 16l/100kms, which I feel is fantastic. However, it has become apparent that the Carter is too worn to provide the drivability I would like on initial start up & at low sped cruise speeds.

So, an Edelbrock has been proposed & ordered - hopefully it will arrive & be fitted this week, just in time for the big run to Cooly Rocks On.

I'll keep you posted...

  • Like 1
Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Tired of these Ads? Purchase Enhanced Membership today to remove them!
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue.