some of you might remember the air sucking issue i experienced last fall, i went thru 3 intake gasket sets and even with the thick ones from Best Gaskets (14046 E), it still sucked air. not as much as with the thin metal ones, but enough that the engine would stall when brake cleaner sprayed on between manifold and cyl.head.

now, i took the manifold down again, cleaned the surfaces and mounted it without gaskets but with marking paint on the head can now clearly see that the 2 surfaces are uneven and only seats correctly on the 8 spots where the bolts are. looks like the manifold was tightened too much.

i have to find a machine shop that can make these surfaces even.

Views: 150


Reply to This

Replies to This Discussion

How are the surfaces in heads? That could be checked with metal ruler.

did not check that yet, but i guess the manifold side is more prone to be uneven.

I would double the gasket thickness ( two thin or two thick gaskets both sides ) and see if that would stop the vacuum leak — as you know you manifold or head matching surfaces  are somewhat irregular from your matting  paint test 

A good trouble shooting matting test—- for sure 

Should be the an easier fix than other options if it works — worth a  try ! 
A machine shop can plane the manifold and the head but much more involved and some expense as well 

Not sure if you need to be doing both heads and the intake surfaces 

Machine shop will advise on that 

Many have issues with our intake manifold seal  ( to many )  leaking air ( vacuum leak ) which cause engine performance issue ( cylinders running lean and hotter than normal ) 


after a winter of filing and fidling both surfaces of the intake manifold it still sucks air on one side, not as much as before, but still not a good idle when hot.

when you look at the new pics, the marking paint test before i mounted the manifold wasn't that bad, especially when you compare it withe the first pics.

guess i have to find a machine shop in my area :(


Taking look at your photos...have the forward ports been ground on?  They look off-set a smidge to me, but might be camera angle. 

These Caddy intakes are interesting to me. The opposite of a performance manifold. Short runners heading mostly uphill.   Works good for torque, not so good for revs.  

But, of course, who takes their 390 or 429 to redline? Even the transmission short-shifts to prevent that. 

The red line on both the 390 and 429 is ——4,600 rpm so who is looking for revs from these engines ?

These engines are about torque not revs at that redline 

480 lbs of torque is a lot for any gasoline engine to be making

Torque is addictive I have been told —making our year Cadillacs a  very unique driving experience

The 429 engine with the TH-400 trans is an amazing unique combo and driving experience  and why I own mine for 59 years 


Tony, I totally agree with you on the torque.  That's a main reason these cars feel so nimble.  

My former 1961 Series 62 coupe with only 25k original miles did not feel anywhere as snappy as does my '64.   Yes, it's a different engine and different transmission. That's my point. The 429 and TH400 is a great combination. 



  • Add Photos
  • View All


KleerView/OptiKleen Bottle Location

Started by Logan Robb in 1963/64 Cadillac Specific Discussion. Last reply by Logan Robb 6 hours ago. 3 Replies

I just received a repop KleerView bottle and label for my 64 Fleetwood this morning. Wondering where the best location for this bottle would be? Or rather, where was it most commonly installed?I…Continue

Current 1963/64 Cadillac Listings on eBay

Started by Jason Edge in 1963/64 Cadillac Specific Discussion. Last reply by Jason Edge 20 hours ago. 1 Reply

To see all 1963/64 Cadillacs Listed on eBay in the USA…Continue

Tags: ebay

1964 A/C Delco Parts book for Deville

Started by Mark Bartlett in General Discussion. Last reply by Jason Edge yesterday. 1 Reply

Is there a place to go to buy or look at original parts book ThanksssContinue

differential seal

Started by Al zink in 1963/64 Cadillac Specific Discussion. Last reply by Al zink on Monday. 2 Replies

Can anyone provide me with a good source for a differential seal for my 63 cadillacThanksContinue

Blog Posts

Lower Front End Ball Joints

Posted by Logan Robb on May 11, 2023 at 9:04am 7 Comments

Good Morning all! 

I took the 64 into the shop to have some adjustments completed and in the process decided to have the lower ball joints replaced as was recommended the last time I had it in. I ordered the parts and came into the shop. They quoted me nearly $500 to replace those lower ball joints requiring nearly 4hrs of labor. Now this is a reputable shop and they know me by name here and they will continue to get my business. I am just questioning what on earth is…


1964 power steering sector rebuild

Posted by CHRIS CARLSON on March 20, 2023 at 11:32pm 3 Comments

 I'm having my steering sector rebuilt, and considering changing it from 20-1 ratio 4.2 turns lock to lock to 3.5 turns lock to lock @ 16-1 ratio, If i change from a 3 1/4" box to a 3" box i could have a 14-1 Ratio steering response would be faster, shorter distance to turn the wheel to get a response,   has anyone done this? and how do you like it? thank you

1964 Daville dashboard clock

Posted by Willem Bol on March 13, 2023 at 11:33am 2 Comments


Can somebody help me finding a dashboard clock  for my 1964 Cadillac DeVille Convertible?

Thank you in advance,

Willem Bol

The Netherlands

Does anyone know where I can get the bushings for AC compressor mount on the 429?

Posted by Robert Schles on February 21, 2023 at 11:45am 2 Comments

I've looked at the usual rubber sources but couldn't find any. 


  • Add Videos
  • View All

© 2023   Created by Jason Edge.   Powered by

Badges  |  Report an Issue  |  Terms of Service