1992 Buick Roadmaster sedan Vortec head/Cam swap questions
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Joined: Feb 2009
Posts: 11
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Car: 1992 Buick Roadmaster Sedan Limited
Engine: TBI 350
Transmission: Tremec T56
Axle/Gears: 3.73s with an Auburn posi
1992 Buick Roadmaster sedan Vortec head/Cam swap questions
Been searching and reading a lot about the conversion to vortec heads on the TBI 350 and I think I want to go through with it, so two questions for now.
1) I know you need to get a different intake to use with the vortec heads, so do I need EGR? I have to pass emissions, but they do not check anything under the hood, just stick the sniffer in the tailpipe. Would I be able to pass the sniffer without EGR?
2) Been reading that the heads need to be milled down (and a thin head gasket used) for the 305 (L03) to keep compression at the desired level. Would this also be true for the 350 (L05) if I used heads off a vortec 350?
3) What cam would you recommend for a heavy car such as the Roadmaster, it weighed in at 4600lbs with me and a half tank of gas. I need to keep some low end power to get this car goin.
Thanks in advance.
1) I know you need to get a different intake to use with the vortec heads, so do I need EGR? I have to pass emissions, but they do not check anything under the hood, just stick the sniffer in the tailpipe. Would I be able to pass the sniffer without EGR?
2) Been reading that the heads need to be milled down (and a thin head gasket used) for the 305 (L03) to keep compression at the desired level. Would this also be true for the 350 (L05) if I used heads off a vortec 350?
3) What cam would you recommend for a heavy car such as the Roadmaster, it weighed in at 4600lbs with me and a half tank of gas. I need to keep some low end power to get this car goin.
Thanks in advance.
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From: Mesa AZ
Car: 87 Firebird, 90 bird coming soon
Engine: 355 Chevy Vortec Heads TPI, LT1 inj
Transmission: 700r4
Axle/Gears: 2.77 posi 9-bolt
Re: 1992 Buick Roadmaster sedan Vortec head/Cam swap questions
If you have emissions, the egr is needed to reduce NOx. If you are using the vortec heads on a 350, you don't need to do anything in terms of milling. As for the cam, a good LT1 cam or LT4 Hot cam would do nicely. Remember to change your valve springs with the cam to be able to handle the lift.
Thread Starter
Junior Member
Joined: Feb 2009
Posts: 11
Likes: 0
Car: 1992 Buick Roadmaster Sedan Limited
Engine: TBI 350
Transmission: Tremec T56
Axle/Gears: 3.73s with an Auburn posi
Re: 1992 Buick Roadmaster sedan Vortec head/Cam swap questions
If you have emissions, the egr is needed to reduce NOx. If you are using the vortec heads on a 350, you don't need to do anything in terms of milling. As for the cam, a good LT1 cam or LT4 Hot cam would do nicely. Remember to change your valve springs with the cam to be able to handle the lift.
Now for the EGR, the reason I was asking about going without it is I found the following on the Impala SS Forum
Did you know that the stock LT4 engine did not come with an EGR?
There's a GM block off plate kit for the EGR delete.
The EGR is necessary with the stock B-Body cam but the EGR is not necessary with a bigger cam and proper tune.
Removing the EGR on a stock engine = bad.
Removing the EGR on a heads/cam engine = good.
There's a GM block off plate kit for the EGR delete.
The EGR is necessary with the stock B-Body cam but the EGR is not necessary with a bigger cam and proper tune.
Removing the EGR on a stock engine = bad.
Removing the EGR on a heads/cam engine = good.
Thread Starter
Junior Member
Joined: Feb 2009
Posts: 11
Likes: 0
Car: 1992 Buick Roadmaster Sedan Limited
Engine: TBI 350
Transmission: Tremec T56
Axle/Gears: 3.73s with an Auburn posi
Senior Member
iTrader: (1)
Joined: Jan 2007
Posts: 684
Likes: 1
From: Mesa AZ
Car: 87 Firebird, 90 bird coming soon
Engine: 355 Chevy Vortec Heads TPI, LT1 inj
Transmission: 700r4
Axle/Gears: 2.77 posi 9-bolt
Re: 1992 Buick Roadmaster sedan Vortec head/Cam swap questions
May need to put one on as a mock-up to get past emission inspections. If your other Forum has people that have done this with an LT4 cam, then follow their advise. If not, you might need to use the EGR valve with the way it was intended. As for the springs, you would want to match them for the lift.
Thread Starter
Junior Member
Joined: Feb 2009
Posts: 11
Likes: 0
Car: 1992 Buick Roadmaster Sedan Limited
Engine: TBI 350
Transmission: Tremec T56
Axle/Gears: 3.73s with an Auburn posi
Re: 1992 Buick Roadmaster sedan Vortec head/Cam swap questions
May need to put one on as a mock-up to get past emission inspections. If your other Forum has people that have done this with an LT4 cam, then follow their advise. If not, you might need to use the EGR valve with the way it was intended. As for the springs, you would want to match them for the lift.
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