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My First 455


Guest Scott Marencic

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Guest Scott Marencic

Hey everybody, I just got my hands on a 455 out of a '72 Electra 225. I am putting this in my 1971 skylark, and using a 700-R4 trans and my open 10 bolt w/2.56 gears. I started my 455 search planning on using just the block and crank to do a hi-po rebuild, but so far the engine looks to be in pretty good shape. It has 119,000 Miles on it. I do have a couple of questions regarding this motor however.<P>1. Do I need different frame mounting pads for this engine to go in? I took the motor mounts from the donor car.<P>2. This engine has what looks like a smog pump with it. Do I need this for it to run properly? My main concern is that I don't have as much underhood clearance as the Electra from which it came.<P>3. Can I transfer all of my accessories and brackets over to the new motor? <P>4. I am getting 12-15 MPG with my 350. What kind of milage should I expect with the 455?<P>5. The 455 has the Q-jet on it still. I have a Carter AFB 750CFM on my 350. Should I put the Carter on the 455, or should I leave the Q-Jet in place? (i.e., best mix of power and economy and drivability)<P>6. Does anyone want to venture a guess as to what 1/4 mile times I could get with this? I am running 15.8 w/the 350.<P>Thanks in advance for any info you guys can give me!<P>-Scott Marencic<BR> LDPosse@juno.com<p>[This message has been edited by Scott Marencic (edited 01-15-2001).]

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first thing, what is this going into. i will guess that it is a skylark of some year. <P>you will need 455 motor mounts and frame mounts for your year skylark. various dealers sell these.<P>mileage will be around 15 mpg on the high way if the motor is in perfect working condition with a good tune up and proper carb set up. i have a 1973 riv with 140 K miles that gets 16 mpg highway. and a moderately built skylark with a 455 that gets 8. so it depends on the set up also.<P>do not get rid of the Q-jet. it is a 800 cfm carb and can be modified to flow 850 cfm. it is better in my opinion that the carter. also you are stepping backward in cfm with the carter.<P>i do not think that you need the smog pump, but i am not sure. <P>also the brackets for the 455 are more than likely different than the 350 due to the 455 being a larger motor, but i am not sure. that is easy to find out. i would guess that you could use the alternator ans the power steering pump from the 350, but you should have taken that stuff from the donor car. then you would not have to guess at what would fit.<P>also did you take the TH-400 tranny from the electra? installing the motor is an experience. make sure that you geta short tail shaft TH-400 tranny for the skylark application. also buy new motor mounts, especially if you are going to modify the engine.<P><BR>

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If you use the 700 trans ,you will need an adapter ,unless you got one of the rare ones that have a dual pattern. Motor mounts can be purchased from TA or Poston and you can use the brackets that come with the 455for most of the accessories. Use the Q-jet ,as it is set up for that engine ,and is a good carb. Gas mileage with a 2.5 axle should be 16-17 . I have a 2.56 in my 37 with a 455 and it pulls 17-18 but it is 400 pounds lighter than your Skylark

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The 455 will fit just fine. I would get another intake like a stock '71 or an Edelbrock or Offenhauser unit. They don't have the smog passages.<P>Tomsriv

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Guest Scott Marencic

Thanks all for the info. Now that I have had a chance to tear into the engine, it does look like I will need a rebuild on this motor, since I tend to run my car pretty hard. A cold compression test gave me the following #'s<BR>1 - 85 2 - 80<BR>3 - 70 4 - 65<BR>5 - 75 6 - 60<BR>7 - 100 8 - 105<P>I also pulled the #2 main bearing cap and the #4 and #5 rod bearing caps. The rod bearings have a darker gray appearance, and there are some spots where it looks like wear particles have made spots in the bearing surface. The main bearing has a grooved apprearance, but they are not deep enough to catch my fingernail when dragged across it.<BR>Another issue is the cam, I think it must be worn signifigantly, I cranked the motor over by hand to make sure I didn't have any worn-off lobes from a collapsed lifter, etc. The valve lift on almost all of the valves was very small. I may pull the cam is a few days to see how it looks.<BR>As far as the cylinder bores, I can still see the crosshatch at the bottom of the cylinder bores, but they are smooth and a few look slightly scored in the area of the ring travel.<BR>If anyone has any input on condition of the bearings, it would be greatly appreciated. I am not sure how to "read" the condition of bearings, but I didn't think the wear pattern I found on the main bearing was particularly good. I have taken some pictures of them, and I will post them once they are developed and I get them scanned in. -Scott Marencic LDPosse@juno.com

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I disconnected the airpump of my '72 Riviera GS and had no problem. When using your stock intake manifold you can fit an earlier (I believe '71)type intake gasket. This will block off some of the unneccessary heating passages from the exhaust. This will get you some extra horses.

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i took the belt and smog pump off of my 72 riviera with no adverse effects. i took the little pipe and smashed it shut then had my friend weld a bead across it. now it starts with a half turn of the starter when its warmed up. it didn't do that before.

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  • 2 years later...

My 1st car was a 69 Electra 225 w/430-4bbl engine turbo 400 trans and 2.78 rear. When I bought the car it got 8 mpg. I rebuilt it cheap put in a used racing cam, dual exhaust and a few other minor changes and remember on one trip to Flint for the Buick nationals I got 19.7 from Milwaukee there and back. So milage is possible.(most of the trip was taken at 80-90mph don't tell the cops)

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