Repost on which engine 455 or 350
May 21st, 2012, 06:57 PM
#1
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Location: abingdon, va
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Repost on which engine 455 or 350
I am trying to decide which engine to put back into my blue 72 cutlass S.
So everyone gets a vote, I have some specs on the motors. My concern is I will put the 455 in and the performance will only be marginally better then the 350. I and my grandson want to do this right the first time through.
I purchased the car in March. Sooo! Long story short , I thought the 350 was bad. It was using a lot of oil and smoking, especially the right bank. Well, I am still kicking myself over this one. When I finally changed the oil before a 200 mile run to a car show, I found the dip stick was marked wrong. It was an aftermarket stick and well it was about 2 quarts over full. So I was topping her off. With the correct oil, 5 quarts its hardly using any oil and no smoking. Beware the dip stick!!!
My plans are to put a 200-4r behind one of these motors. The rear gear is a 3.08 open carrier. Maganaflow 2.5" exhaust and mufflers. If I go with the 455 I will need to buy headers and probably cut the H pipe on the exhausts to make it fit. any thoughts on this ?
Of course I seized the opportunity to purchase a 72 olds 455 rebuilt with about 16k miles on it, been setting for about 6 years, started some during this time, originally in a 72 wagon he owned. I bought the whole car(78 88) he had stuffed it in. The original owner (mechanic) rebuilt the engine. I drove the car and it run good considering it had cats and quite exhaust, a little blow by, but otherwise good. I feel the 750 holley is over jetted for this motor, he just put it on to sell it. So it wasn't tuned for the motor.
The 455 engine has the edlebrock 2152 cam kit, 2151 intake, 750 holley Gm HEI and standard dished pistons (assume stock). With about 16k miles, possible more miles since the valves and valve covers had more film on them then I would expect for a engine with 16 k miles. All plugs are black. Here are the compression and leak down tests, all leak down test was done with 100 psi.
cyl, compression , leak down pressure ,% leakage
1 135 92 8
8 130 92 8
4 130 95 5
3 135 95 5
6 130 90 10
5 137 95 5
7 137 90 10
2 130 90 10
the 350 engine has an edlebrock rpm intake, hooker headers 2.5", 650 holley, nice cam, little thump!
don't have specs, pertronix hei distributor. Chrome pan, valve covers, etc.The rocker assemblies are very clean, it doesn't appear to have many hours on this motor. Plugs now look ok, 1 and 8 look right, all rest appear to be running a little rich (blacker and darker tan). It has dish pistons also, assume stock. Here are the numbers
cyl, compression, leak down pressure, % leakage
1 145 98 2
8 150 98 2
4 155 98 2
3 140 99 1
6 145 100 0
5 140 100 0
7 140 96 4
2 140 97 3
Both engines are out, My grandson wanted to learn how to pull them, so he helped with both. We still need to move the brake proportional valve as it is to close to the header for my liking. And repair the air conditioning box, as it is destroyed, not by us. Although we are some what dangerous with all that engine and tranny weight moving around.
So please give me your opinion, hints, tricks, concerns based on what I know about the engine and goals. All input is appreciated.
So everyone gets a vote, I have some specs on the motors. My concern is I will put the 455 in and the performance will only be marginally better then the 350. I and my grandson want to do this right the first time through.
I purchased the car in March. Sooo! Long story short , I thought the 350 was bad. It was using a lot of oil and smoking, especially the right bank. Well, I am still kicking myself over this one. When I finally changed the oil before a 200 mile run to a car show, I found the dip stick was marked wrong. It was an aftermarket stick and well it was about 2 quarts over full. So I was topping her off. With the correct oil, 5 quarts its hardly using any oil and no smoking. Beware the dip stick!!!
My plans are to put a 200-4r behind one of these motors. The rear gear is a 3.08 open carrier. Maganaflow 2.5" exhaust and mufflers. If I go with the 455 I will need to buy headers and probably cut the H pipe on the exhausts to make it fit. any thoughts on this ?
Of course I seized the opportunity to purchase a 72 olds 455 rebuilt with about 16k miles on it, been setting for about 6 years, started some during this time, originally in a 72 wagon he owned. I bought the whole car(78 88) he had stuffed it in. The original owner (mechanic) rebuilt the engine. I drove the car and it run good considering it had cats and quite exhaust, a little blow by, but otherwise good. I feel the 750 holley is over jetted for this motor, he just put it on to sell it. So it wasn't tuned for the motor.
The 455 engine has the edlebrock 2152 cam kit, 2151 intake, 750 holley Gm HEI and standard dished pistons (assume stock). With about 16k miles, possible more miles since the valves and valve covers had more film on them then I would expect for a engine with 16 k miles. All plugs are black. Here are the compression and leak down tests, all leak down test was done with 100 psi.
cyl, compression , leak down pressure ,% leakage
1 135 92 8
8 130 92 8
4 130 95 5
3 135 95 5
6 130 90 10
5 137 95 5
7 137 90 10
2 130 90 10
the 350 engine has an edlebrock rpm intake, hooker headers 2.5", 650 holley, nice cam, little thump!
don't have specs, pertronix hei distributor. Chrome pan, valve covers, etc.The rocker assemblies are very clean, it doesn't appear to have many hours on this motor. Plugs now look ok, 1 and 8 look right, all rest appear to be running a little rich (blacker and darker tan). It has dish pistons also, assume stock. Here are the numberscyl, compression, leak down pressure, % leakage
1 145 98 2
8 150 98 2
4 155 98 2
3 140 99 1
6 145 100 0
5 140 100 0
7 140 96 4
2 140 97 3
Both engines are out, My grandson wanted to learn how to pull them, so he helped with both. We still need to move the brake proportional valve as it is to close to the header for my liking. And repair the air conditioning box, as it is destroyed, not by us. Although we are some what dangerous with all that engine and tranny weight moving around.
So please give me your opinion, hints, tricks, concerns based on what I know about the engine and goals. All input is appreciated.
May 21st, 2012, 08:35 PM
#2
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Join Date: Sep 2010
Location: Shorewood, Il.
Posts: 3,057
I'm gonna start with; why cats on a '72? No way were they required, and probably why the plugs were black!
That 455 wasn't jetted for cats, and you probably rescued it!
I'd go back with the 350, as no more money to spend, 200r4 will last longer, seems in better shape, and will go back in, without problems.
Fuel isn't gonna get cheaper!!
Show your Grandson how to pull the 455 down, hone it, re-ring it, and sell it, knowing you can guarantee it, or bag it in case something happens to the 350.
A couple guys on here could turn you on to a better cam to go with your combination, so you could feel better seat-of-the pants feel!
A 3:42 posi would really wake everything up, and let you take advantage of the O.D.!
That 455 wasn't jetted for cats, and you probably rescued it!
I'd go back with the 350, as no more money to spend, 200r4 will last longer, seems in better shape, and will go back in, without problems.
Fuel isn't gonna get cheaper!!
Show your Grandson how to pull the 455 down, hone it, re-ring it, and sell it, knowing you can guarantee it, or bag it in case something happens to the 350.
A couple guys on here could turn you on to a better cam to go with your combination, so you could feel better seat-of-the pants feel!
A 3:42 posi would really wake everything up, and let you take advantage of the O.D.!
May 22nd, 2012, 04:45 PM
#3
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Join Date: Feb 2012
Location: abingdon, va
Posts: 12
Thanks rickman48 for your response. The previous owner had the 72 455 in a 78 olds 88. My same thought, why cats, he lives in Tn where there is no inspections.
Was thinking about a different gear, later on. Need to get it back running for car shows that we want to go to. I had a 66 olds 442 4 speed, 411 gears, when I was 20. Man I had fun with that car, it had a lot of power. Own it for a while, change 4 speed to turbo 400 with dual gate shifter.
Was thinking about a different gear, later on. Need to get it back running for car shows that we want to go to. I had a 66 olds 442 4 speed, 411 gears, when I was 20. Man I had fun with that car, it had a lot of power. Own it for a while, change 4 speed to turbo 400 with dual gate shifter.
May 25th, 2012, 03:52 PM
#4
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Join Date: Aug 2007
Posts: 2,250
I love 350s. But, there is an old saying, "There is no substitute for cubic inches". a 455 with it's 500 ft/lbs of torque and a 3.08 gear is an awesome street combo. Why the OD trans? Keep it simple. No need with that gear, IMO. Also, you really don't need the headers with the 455, duals will be fine. The car will be an absolute blast to drive.
May 25th, 2012, 07:11 PM
#5
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Location: abingdon, va
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thanks for responding, We plan to drive the car a lot. So I was hoping to increase the mileage when we were out on the interstate driving. Might ever drop in a lower gear later on this fall. The olds is already set up for hooker headers that are sized for the 350 , 1 5/8" tubes with 2.5 " collector. So I was thinking I would need a new set of headers to match the 455 taller deck height and width difference. I don't think it would be much of an issue if it wasn't for the H pipe on the exhaust. It might have enough floor pan space , not for sure.
June 8th, 2012, 01:29 PM
#12
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Location: abingdon, va
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headers not working.
Decided to go with 455. Just put it in this morning. Thought I could work with the 350 headers , but they have clearance issues on the air conditioning box and driver frame rails. Any good Ideals on what headers fit best for the 72 cutlass.
June 14th, 2012, 07:02 PM
#14
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Got the flowtech from jegs installed today with the help up my grandson. I had to massage one of the driver's side lower header pipes just a little with my engineering hammer. The area just past the radius bend was just touching the frame. No issue on the passenger side. They are about 4 inches shorter in length then the 350 hooker headers. So it will be going to the muffer shop next week. Fired it up, sounds good with open headers!! My grandson said he liked the sound, and I should run it that way! He's 15 !!
Since I moved the cross-member back to fit the 200r4, I now have issues with the emergency brake cable fitting properly.
Drive line fit well, no issues there.
Will try to button her up tomorrow and get it down off the jack stands.
Since I moved the cross-member back to fit the 200r4, I now have issues with the emergency brake cable fitting properly.
Drive line fit well, no issues there.
Will try to button her up tomorrow and get it down off the jack stands.
June 15th, 2012, 06:33 AM
#15
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Location: Poteau, Ok
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On the e-brake, there is a hook on the passenger side trans xmember, if you fabricate a 1" hook that you can bolt into that hole, then all you need to do is adjust the cable tighter. I used a pick-up tie-down hook and modified it.
June 15th, 2012, 09:03 AM
#16
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Location: Northern VA
Posts: 48,238
I'll offer that GM typically does not use different parts if the same one works. In this case the TH400 cars used different front and intermediate ebrake cables due to the crossmember relocation. Get the cables for a 67 with TH400.
June 15th, 2012, 01:39 PM
#17
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Thanks all for the info and suggestions. I moved the e brake cable under the cross member and rearranged the cable support hooks, readjusted the cable. It all seems to work now. Will look it over again before I get it down off the stands. We spent most of this morning redoing the metric retrofit on the shifter cable bracket we done 3 days ago.
So maybe Monday the tires will touch the ground again.
So maybe Monday the tires will touch the ground again.
June 15th, 2012, 11:19 PM
#18
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Location: OKC, OK
Posts: 303
I'd have done the 455, and you knew you were leaning that way anyway and why you posted in the Big Block section huh??? But, that 350 sure seems to be in good shape too. What are you plans for it now?
I'm also curious as to how long a 200r4 will hold up to a 455. Unless you're just wanting to drag race, I think I'd save my money, keep the 3.08's which are fine with a Non OD Th400 that will stand up fine to the torque of a 455 and just enjoy the car. 455 has enough grunt right off idle to still set you back in the seat a bit with 3.08's.
I'm also curious as to how long a 200r4 will hold up to a 455. Unless you're just wanting to drag race, I think I'd save my money, keep the 3.08's which are fine with a Non OD Th400 that will stand up fine to the torque of a 455 and just enjoy the car. 455 has enough grunt right off idle to still set you back in the seat a bit with 3.08's.
June 17th, 2012, 06:05 PM
#19
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Hotrodpc, No comment on the forum question. Going to keep the 350 and 350 auto as a spare for a while. I also found a 66 cutlass that I might play around with. I think the 200r4 will hold up just fine to the 455 it has all the new updated internals. Got it mainly to get a few more mpg when we cruise to far away locations to show the car.
June 17th, 2012, 06:12 PM
#20
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Got the exhaust pipes all hook up today, and got it out on the road today. Got some fine adjustments to work out on the tv cable. Sooo my speedometer doesn't work now. Going to check it out tomorrow, I suspect the cable end is stripped. I checked it for the right gear, but dang I didn't check it for damage on the cable end.
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