Cadillac 472 emissions removal

[tvincent]

Hello, I have an all original 1972 Cadillac Sedan Deville with the 472 motor in it. Great motor, but I know that it can be better if emissions controls are removed. Im not sure if it has and AIR pump. Im just wondering if anyone has removed these and experienced an improvement in power.

[blue_eldo]

What year is it? Removing the A.I.R. pump will only help slightly. You need to replace the crank pulley to do so as well as obtain different belts and install blocking plugs in the heads.
Lower hanging fruit is to remove the CAT and upgrade the exhaust to 3" or duals. Upgrade to an HEI distriubutor with a recurve. a Low restriction air filter or cold air intake. Remember everything happens with these beasts below 3500 rpm.

[tvincent]

Its a 1972. It already doesn't have cats, but it does still have the single small exhaust. I have also upgraded to an HEI distributor as well. Thanks very much for the advice though.

[blue_eldo]

A 72 may have EGR. My 72 500 has a 75 engine in it so I am not sure about a your 72 472. There is an opininon that I have heard and share is that the EGR acually helps these engines more that hurting them by allowing for additional spark advance without detonation. This helps gas milage during moderate to heavy throttle applications.

Another thought would be to replace the timing chain with a Cloes unit that different key notches in the crank gear for advancing the valve timing. The timing covers are nasty removals however.

[KiwiCadi]

My '75 SDV has had the catalytic converter, smog pump (aka A.I.R. pump??) and the EGR removed as none of these are required over here. That along with a decent tune, new dizzy cap/coil/module/wires and a rebuilt carb have made my car a different beast for the better.

It still has the single exhaust system at the moment. I don't know if anyone has put duals on a '75 SDV.

[guidematic]

1973 was the first year for EGR, and in those early years did not do anything for performance. Just look at the drastic power drops from '72-'73.

Removal of the AIR pump will do nothing for performance, plus it requires re-arrangement of all the pulleys. Not worth the effort.

I think you have already done the best thing you can do for these engines, and that is a switch to HEI. It was certainly the best thing I did with my '70 472, and it is no slouch for power to begin with.

Also, you can plug the advance into manifold vacuum if it uses ported vacuum now. This will give much better tip in response at lower RPM and also help fuel economy.

As far as the exhaust goes, a set of 2 1/2" duals will also give great benefit, but Cadillac did not make it esy to do this because of the offset transmission mounting structure and offset gas tank.

Also, on the issue of airflow, take off the breather lid and replace it with a smaller one that covers just the filter. These air cleaners simply cannot flow enough air to satify a gulping 472 at WOT. The snorkel allows only 380 cfm. That 472 can swallow almost twice that.

Mike

[BluEyes]

Originally Posted by blue_eldo

A 72 may have EGR. My 72 500 has a 75 engine in it so I am not sure about a your 72 472. There is an opininon that I have heard and share is that the EGR acually helps these engines more that hurting them by allowing for additional spark advance without detonation. This helps gas milage during moderate to heavy throttle applications.

EGR helps light-mid throttle power. At heavy throttle, EGR is shut off entirely because it would hurt wide open HP.

As far as power goes - '72 and '73 were both rated at 220 net HP. The "drop" came in '72 when ratings were changed from gross to net and the car went from 375hp to 220hp on paper. The difference was mostly due to the new tests that measured hp closer to what the car sees, kinda like the difference between gross and net pay on your paycheck. I have read that '72 made 345hp when measured the same way as the '71. Still a loss, but not as much it might seem.

[crucialjp]

What do you have to do to the pulley's to get this to work? I just put a 472 in my 80CDV and I left the smog pump off and the ac compressor for the moment, but it looks like everything still lines up. I can see I'll need one shorter belt for the crank pully but that's all it looks like for now.

[drmenard]

You should have started a new thread, but here it goes... to get rid of the smog pump you need to change the crank and waterpump pulleys...get them off a 1977 to 79 cadillac 425 motor... they will bolt on ...only 2 belts are needed... with the set-up you have now , if you leaveoff the smog pump nothing turns the waterpump or alternator

[crucialjp]

Thanks drmenard for the response, I will start a new thread about this because I have another question.