Any concerns going from 425 to 455 ?

nonhog · October 3rd, 2008, 02:15 PM

I have a 65 Cutlass with a 425 (year ?) and its pretty tired , I have a 455
(1970) that came with the car . I might toss in the 455 and see how it does, anything to be careful of or look out for ?
Seems it would be a straight forward swap ? thanks!

Oldsmaniac · October 3rd, 2008, 02:18 PM

They are the same externally

Run to Rund · October 4th, 2008, 09:38 AM

Balancer on the front and flexplate/flywheel are different. Different water pump snout lengths for different year ranges.

Oldsguy · October 4th, 2008, 08:13 PM

Go for it, and good luck.

joe_padavano · October 5th, 2008, 08:21 AM

Quote:

Originally Posted by Run to Rund

Balancer on the front and flexplate/flywheel are different. Different water pump snout lengths for different year ranges.

The water pump length varies due to A/C or non-A/C. It is not related to year or engine size. Use the pump that matches the brackets and pulleys you plan to use.

Run to Rund · October 5th, 2008, 09:42 AM

My experience has been that in 66, for example, all water pumps are about 5.12" height; AC pumps have a .75" diameter circle near the pass side port. I think it was about 68 when Olds went to the 5.62" height.

nonhog · October 6th, 2008, 09:32 AM

Thanks guys , I am pretty sure both engines have pulleys on them .
So I should be able to "drop" in 455 but if nec. steal parts of the 425 ?
I am not worried.
Now the important stuff run headers ?(got em) Run the 2 spd . till it dies?
put in the T350 at the same time ? (not real hot on adding the floor shifter)

Just stuff for me to figure out !

joe_padavano · October 6th, 2008, 10:24 AM

Quote:

Originally Posted by Run to Rund

My experience has been that in 66, for example, all water pumps are about 5.12" height; AC pumps have a .75" diameter circle near the pass side port. I think it was about 68 when Olds went to the 5.62" height.

The difference in water pump heights is a function of A/C vs. non-A/C. It is not generally related to the year. The pump height is matched with the brackets and pulleys. Use them all as a matched set.

Run to Rund · October 7th, 2008, 05:58 PM

Joe, if you get to NM or NV, I will show you some AC pumps for 66 that are 5.12" high, just like the non-AC pumps. I don't know much about any other years. Since I never use AC pulleys either, I suppose it is possible Olds used 5.62" pumps then but the GMPD parts book doesn't list anything but the 5.12" high pump in 66 (388182 regular, 388183 AC).

joe_padavano · October 7th, 2008, 07:44 PM

Quote:

Originally Posted by Run to Rund

Joe, if you get to NM or NV, I will show you some AC pumps for 66 that are 5.12" high, just like the non-AC pumps. I don't know much about any other years. Since I never use AC pulleys either, I suppose it is possible Olds used 5.62" pumps then but the GMPD parts book doesn't list anything but the 5.12" high pump in 66 (388182 regular, 388183 AC).

Actually, the A/C pump is also the HD cooling pump. My W-30, for example, uses a long nose "A/C" water pump in a non-A/C application. I was simplifying my response (since I'm lazy

), but my response remains the same: Use the pump, pulleys, and brackets as a matched set.

October 3rd, 2008, 02:15 PM	#1 (permalink)
nonhog Registered User Join Date: Apr 2008 Location: PNW Posts: 94	Any concerns going from 425 to 455 ? I have a 65 Cutlass with a 425 (year ?) and its pretty tired , I have a 455 (1970) that came with the car . I might toss in the 455 and see how it does, anything to be careful of or look out for ? Seems it would be a straight forward swap ? thanks! __________________

October 3rd, 2008, 02:18 PM	#2 (permalink)
Oldsmaniac Registered User Join Date: Oct 2005 Location: NJ Posts: 702	They are the same externally __________________ OCA Member 2587 '59 98 conv. '66 Delta Fact.4spd '66 Delta conv. '67 442 post trac pac '67 442 conv. '68 Cutlass conv. '70 Rallye 350 '92 Custom Cruiser

October 4th, 2008, 08:13 PM	#4 (permalink)
Oldsguy Hot Rodder at heart Administrator Join Date: May 2004 Location: Lees Summit MO Posts: 5,360	Go for it, and good luck. __________________ Dan '77 Cutlass Supreme '46 2 door "The rocket 455.....it's a sledgehammer approach to a thumbtack world" LuxBlue of HAMB.

October 6th, 2008, 09:32 AM	#7 (permalink)
nonhog Registered User Join Date: Apr 2008 Location: PNW Posts: 94	Thanks guys , I am pretty sure both engines have pulleys on them . So I should be able to "drop" in 455 but if nec. steal parts of the 425 ? I am not worried. Now the important stuff run headers ?(got em) Run the 2 spd . till it dies? put in the T350 at the same time ? (not real hot on adding the floor shifter) Just stuff for me to figure out ! __________________

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October 4th, 2008, 09:38 AM	#3 (permalink)
Run to Rund Registered User Join Date: Mar 2008 Posts: 337	Balancer on the front and flexplate/flywheel are different. Different water pump snout lengths for different year ranges.

October 5th, 2008, 09:42 AM	#6 (permalink)
Run to Rund Registered User Join Date: Mar 2008 Posts: 337	My experience has been that in 66, for example, all water pumps are about 5.12" height; AC pumps have a .75" diameter circle near the pass side port. I think it was about 68 when Olds went to the 5.62" height.

October 7th, 2008, 05:58 PM	#9 (permalink)
Run to Rund Registered User Join Date: Mar 2008 Posts: 337	Joe, if you get to NM or NV, I will show you some AC pumps for 66 that are 5.12" high, just like the non-AC pumps. I don't know much about any other years. Since I never use AC pulleys either, I suppose it is possible Olds used 5.62" pumps then but the GMPD parts book doesn't list anything but the 5.12" high pump in 66 (388182 regular, 388183 AC).

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