# Horse Increase?



## GTO'n'TRANSAM (Nov 13, 2008)

Hey guys I was wondering if you could tell me if there would be a change in power in a smogged-out engine if the "anti-smog" stuff was gone.

My dad's 1976 T/A 400 is supposedly missing the stuff GM through on it to make it "green" back in the day. My 1967 Lemans is the same way. Someone dropped in a 73 or 74 Pontiac 350. I seriously doubt they put anything extra on there. 

The 400 was rated at only 185HP and the 350 at only 150HP. That just sounds...weak. They sure dont feel like it though.


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## Rukee (Feb 8, 2007)

Not much of a power increase by removing it. Now, the cars are worth much more if that emission stuff is all intact. The HP was low cause that was right in the middle of the gas crunch era.


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## Too Many Projects (Nov 15, 2008)

After 71 the hp ratings are NET as opposed to GROSS before. Much of the decrease was for rating purposes only but the drop in compression from 72 on lowered the hp even more. A smog pump ate a few hp but not enough to even notice after it's removal. A friend of mine bought a 74 vette in 78 and it was a dog. We took the pump off and couldn't tell anything different. I recurved the distributor, bumped the timing up 6 degrees and put a Holley 650 on it and THEN we knew it was different..........


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## raspantienator (Nov 20, 2007)

Cars Like Your Ta Could Be Quickly Brought Up To The Hp #'s. Because Of The Gas Crunch-pontiac Being The One Last Hold-out Interms Of Mega Engines Like The 455, The Cars Did Have Hp Numbers Under 200 But The Torque Was Still Way Up There And With A Little Work Under The Hoop, The Hp Would Also Climb.


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## jetstang (Nov 5, 2008)

I agree with above. The 6X heads from the mid 70s are really good flowing heads with 2.11 valves. The problem was compression and weak cams. Compression bump, cam swap, decent intake and carb and you will make good power out of both motors. The 350 is not a bad motor, but the 400 and 455s are direct drop ins, so everyone thought why keep a 350 when they can have a 455.


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## geeteeohguy (Feb 2, 2008)

The above posts are right on. The main reason for low hp is that it was Net, not Gross hp and low compression and low performance camming. The compression ratio for your TA is 7.6:1, and it has a mild cam. In the transition period of 1975-1985, US car makers was using Band-Aid technology to make engines engineered in the 1950's meet 1970's and 80's standards. After 1985, they got it right, with fuel injection, variable valve timing, DIS ignition, etc. Your best bet would be a slight compression increase and better camshaft. Leave the smog equipment intact for all the reasons stated above.


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## GTO'n'TRANSAM (Nov 13, 2008)

Thanks for the info. Found out yesterday the 350 is actually a '67 389 which is actually a 400. Found my 105 extra horses!


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## jetstang (Nov 5, 2008)

GTO'n'TRANSAM said:


> Thanks for the info. Found out yesterday the 350 is actually a '67 389 which is actually a 400. Found my 105 extra horses!


The 389 would of been better, older motors have the high compression. Now, you have to find out what year the 400 is. And, find out why the 2 barrel is on there. Maybe they took the 2 barrel off the 350 and put it on a good motor. You can do a compression test and find the approximate compression ratio via the cylinder pressure.


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## GTO'n'TRANSAM (Nov 13, 2008)

jetstang said:


> The 389 would of been better, older motors have the high compression. Now, you have to find out what year the 400 is. And, find out why the 2 barrel is on there. Maybe they took the 2 barrel off the 350 and put it on a good motor. You can do a compression test and find the approximate compression ratio via the cylinder pressure.


The engine is a '67 389 from a GTO. The '67 year they bored them out to 400. Some of them had 2 bbl carbs as they were "economy".


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## jetstang (Nov 5, 2008)

I don't think the GTO ever came with a 2 barrel. A 67 400 is a great motor, 4 barrel and cam will soup it up good. I had a 66 Tempest in High School with a 455 2 barrel with 3.55 rear end and tore many a car up. I was a Legend, lol... Not, but I did beat some fast cars. That was the 80s, 15s was fast, now 13s are quick. Times change. You have to do more to be quick with an old car now.


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## 68greengoat (Sep 15, 2005)

jetstang said:


> I don't think the GTO ever came with a 2 barrel. A 67 400 is a great motor, 4 barrel and cam will soup it up good. I had a 66 Tempest in High School with a 455 2 barrel with 3.55 rear end and tore many a car up. I was a Legend, lol... Not, but I did beat some fast cars. That was the 80s, 15s was fast, now 13s are quick. Times change. You have to do more to be quick with an old car now.



In '67 they had 2 400cu, 255hp with 2 barrel carbs. Both 8.6:1 compression. XL/XM engine codes. They both came with automatic transmissions. Let us not forget about the 3x2's for '64 - '66.


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## Old Goat 67 (Feb 2, 2009)

> In '67 they had 2 400cu, 255hp with 2 barrel carbs.


Carb.


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