[Tim66]

Hi guys,hate to bring this up again but here it goes.I am going to change from an 8 bolt to a 11 bolt pump.Which pump should I get,flow cooler or factory?
Thank you for any help,not worried about anything but getting it to run cool.
67 428
Tim

[ZeGermanHam]

Honestly, I think there are a few decent options. My brother and I both switched from stock pumps to the Edelbrock high-flow aluminum pump. Worked great in both of our cars, and being aluminum, it's nice to take some weight off the front of the engine, too. The divider plate needed to be clearanced, but that is typical of just about any brand.

[Tim66]

Thank you ZE
Tim

[nUcLeArEnVoY]

I have an 11-bolt Flowkooler on my '79 Trans Am w/ 400. Clearanced to around .045" with gasket. Moves serious water, and with a CC radiator and heavy duty clutch, my car has trouble warming up. I may have to switch out the 160 for a 180 stat.

[Tim66]

Thank you nucler.
Tim

[Singleton]

Originally Posted by Tim66

I am going to change from an 8 bolt to a 11 bolt pump

You would need to use a 4" 11-bolt pump to keep your pulley alignment. Most 11-bolt pumps are 4.5", so make sure when purchasing

[Tim66]

Thank you Singleton,I'm glad you told me about that important bit of information.I was wondering about that.
Tim

[DogMeister]

In addition to all of the above: cast impeller, not stamped.

[Tim66]

OK guys and gals,I got an aluminum pump with cast impeller .Only problem now is its a long hub were my old one was the short hub. My question is, do I have to change pulleys? Thanks again for any help.
Tim

[Singleton]

Yes, the water pump pulley will be .5” too far forward now.
What’s the part number on your present WP pulley?

[Tim66]

Thank you Singleton,yes I know I have a half inch difference.I was wondering if I have to change all of my pulleys?Seems like I do,maybe a billet system.Any ideas? Thank you
Tim

['ol Pinion head]

Assuming your car has powersteering.... With a tall 11 bolt wp, you're going to need either a "127" non AC 2 groove pulley, or a "128" or "130" AC diam pulley. Also the '67-68 rear alt strap gets replaced with a '69. What do you have for crank pulleys?

[Tim66]

I have pulleys from another 11 bolt WP engine.

['ol Pinion head]

Which 11 bolt pulleys? '71 & later pulleys will not work with '67-70 brackets & pump. '70 V8 Firebird setup is all by itself, thankfully reproduced, except 4 specific pulleys.

Put together first 11 bolt changeover set-up 35 years ago & have shipped out many, many changeovers since.

[Singleton]

Originally Posted by Tim66

I have a half inch difference.I was wondering if I have to change all of my pulleys?

If all you changed was to a taller pump, then a 1970 WP pulley would be all that’s necessary. But without specific info, (pulley numbers), of what exactly you presently have, it’s just a guess. There’s a 1970 “128” pulley in the GTO Parts for Sale section.

[Tim66]

Thanks guys,all that I know is that the engine that I got the parts from is a 73, 400.The crank pulley is only about 1/4 " difference.Sooo are you saying that I only have to change the wp pulley?? Thank you guys I really appreciate the help.
Tim

[Tim66]

OK I have to go and write down some numbers.

[Singleton]

I was assuming that you had a 67 428 with 67 pulleys and brackets, and that you changed to a later 11 bolt timing cover and tall 4.5 water pump. If that was the case, then yes, all you would need is a deeper 1970 WP pulley. But now you’re saying later pulleys and brackets, so I really don’t know what you need. Need more info.

['ol Pinion head]

All comes down to do you want the engine accessories to look very close to a mid '60's Pontiac V8 set-up but run an 11 bolt timing cover & WP, or if appearance is no issue, the '71+ pulleys & brackets can be used.

[Tim66]

ok I have a wp pulley # 9799127XF
Thank you
Tim