TBI cam question guys! - The 1947 - Present Chevrolet & GMC Truck Message Board Network

4:30 · 12-03-2011, 07:16 PM

Ok we got a 350 built for my truck and all i really know about it is its been bored 40 over and has a either 270 or 280 comp cam. It has a stock throttle body on it but the problem im having is i cant really hear the cam. I looked up 350s with a 270 cam on youtube and you could hear theres good but they also have a carb instead of a throttle body. Im still learning on all this (which theres always more to learn) but is there any way to make it be heard more? Thanks!

knightfire83 · 12-04-2011, 09:59 AM

My '94 Chevy has a Comp 268H High Energy Cam in my carbed 383. It lopes pretty good with the idle mixture turned only 1/2 a turn out and timing at 10*btdc.

For the cold weather, I have the mixture screws out 1-1/2 or 2 turns out for driveablilty and it idles smooth as can be.

scotts62 · 12-04-2011, 11:38 AM

If you go too big of a cam in stock TBI you will give it a headache and the computer will think it has a miss and try and make it run right but never will.

tommie · 12-04-2011, 01:40 PM

Quote:

Originally Posted by scotts62

If you go too big of a cam in stock TBI you will give it a headache and the computer will think it has a miss and try and make it run right but never will.

Yes... TBI does not too large of a cam...

4:30 · 12-04-2011, 02:57 PM

But would a 270 or 280 be too big for a TBI? And it runs pretty good but i believe it runs alittle too rich and i only get about 11mpg in town, my thinking is that the throttle body might not be any good or might be clogged up causing the bad gas mileage and running rich. I tought about changing the intake and putting a 4 barrel on it but ive heard thats not an easy swap plus if i didnt like it i wanna be able to put the TBI back on it. I also have a buddy that has a TBI with about a 285 cam and it hits like crazy but i cant figure out why mine wont haha.

hotrod 80 · 12-04-2011, 03:16 PM

I had a carbed 355 with XM 270 HR hydraulic roller (extreme marine)and it was almost unnoticeable . It sounded good , but not really rowdy .

4:30 · 12-04-2011, 03:40 PM

yea that might be my problem. I can hear it alittle and it sounds good but its not quit aggresive enought for my fix ha but i can live with it. I might attempt to go in and put a bigger on it in one day. Maybe a mutha thumper.

12-03-2011, 07:16 PM	#1
4:30 Registered User Join Date: Feb 2011 Location: Ms Posts: 103	TBI cam question guys! Ok we got a 350 built for my truck and all i really know about it is its been bored 40 over and has a either 270 or 280 comp cam. It has a stock throttle body on it but the problem im having is i cant really hear the cam. I looked up 350s with a 270 cam on youtube and you could hear theres good but they also have a carb instead of a throttle body. Im still learning on all this (which theres always more to learn) but is there any way to make it be heard more? Thanks! __________________ God will never take you where his grace will not follow you!

12-04-2011, 09:59 AM	#2
knightfire83 Registered User Join Date: Apr 2011 Location: Lincoln Posts: 7	Re: TBI cam question guys! My '94 Chevy has a Comp 268H High Energy Cam in my carbed 383. It lopes pretty good with the idle mixture turned only 1/2 a turn out and timing at 10*btdc. For the cold weather, I have the mixture screws out 1-1/2 or 2 turns out for driveablilty and it idles smooth as can be.

12-04-2011, 11:38 AM	#3
scotts62 One day... Join Date: Apr 2008 Location: Tuttle, Ok Posts: 9,243	Re: TBI cam question guys! If you go too big of a cam in stock TBI you will give it a headache and the computer will think it has a miss and try and make it run right but never will. __________________ Scott 93 crew cab build Project 62

12-04-2011, 02:57 PM	#5
4:30 Registered User Join Date: Feb 2011 Location: Ms Posts: 103	Re: TBI cam question guys! But would a 270 or 280 be too big for a TBI? And it runs pretty good but i believe it runs alittle too rich and i only get about 11mpg in town, my thinking is that the throttle body might not be any good or might be clogged up causing the bad gas mileage and running rich. I tought about changing the intake and putting a 4 barrel on it but ive heard thats not an easy swap plus if i didnt like it i wanna be able to put the TBI back on it. I also have a buddy that has a TBI with about a 285 cam and it hits like crazy but i cant figure out why mine wont haha. __________________ God will never take you where his grace will not follow you!

12-04-2011, 03:16 PM	#6
hotrod 80 mini truck racer Join Date: Aug 2006 Location: Baytown , texas Posts: 3,010	Re: TBI cam question guys! I had a carbed 355 with XM 270 HR hydraulic roller (extreme marine)and it was almost unnoticeable . It sounded good , but not really rowdy . __________________ 1949 5-window 1969 Camaro 1976 Chevy Luv yellow 1978 Chevy Luv Blue 1976 Chevy Luv Black 1979 Firebird Flooded in Harvey 1999 F350 Dually 2005 GMC Sierra 4.8 RCSB 2014 Explorer (wifes) My build :http://67-72chevytrucks.com/vboard/s...d.php?t=399148 Build #2: http://67-72chevytrucks.com/vboard/s...d.php?t=653583

12-04-2011, 03:40 PM	#7
4:30 Registered User Join Date: Feb 2011 Location: Ms Posts: 103	Re: TBI cam question guys! yea that might be my problem. I can hear it alittle and it sounds good but its not quit aggresive enought for my fix ha but i can live with it. I might attempt to go in and put a bigger on it in one day. Maybe a mutha thumper. __________________ God will never take you where his grace will not follow you!



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