GM847 cam only
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From: Orlando
GM847 cam only so im taking my first step into fixing up the LT1. have about $1500. With a good tune how much power you think ill be putting out with the GM847 and how risky is it with the stock bottom end with new bearings and new rod bolts? or forged pistons are a must? My first step would be cam with bolt ons then, port the heads when i get a little more cash and maybe stroke it or boost it. Whats the best i can get out of a gm847 cam only A4? I know there are tons of threads on this but I would like to know from personal experience with Gm847 with stock bottom end.
When you say Cam Only, do you really mean cam only?
Id think some rockers, better pushrods etc would be in order for that cam.
A stall converter would be need too.
Dont do a cam only install, it makes the LT community look bad.
If your going to pick a bad *** cam like the 847 put some of required goodies with it.
Id think some rockers, better pushrods etc would be in order for that cam.
A stall converter would be need too.
Dont do a cam only install, it makes the LT community look bad.
If your going to pick a bad *** cam like the 847 put some of required goodies with it.
That cam wont be good for more than anything than the sound on a stock bottom end. You could get a smaller cam that will perform much better on the stock bottom end, and still have that awesome sound. The GM 847 cam loves high rpms which a stock bottom end doesn't like as much.
234/242 .576/.595 112 LSA on old magnum lobes. Too big for stock heads and will want more RPM then a stock shortblock will want. Figure around 6700.
If he is rebuilding the shortblock, porting his heads, and doesn't mind revving it high then its not the worse choice possible...but I wouldn't run it on a 350, and definitely wouldn't run it with boost. A modern cam ~226int will make similar top end, more down low, and be just as fast or faster while being easier to tune with better street manners.
If he is rebuilding the shortblock, porting his heads, and doesn't mind revving it high then its not the worse choice possible...but I wouldn't run it on a 350, and definitely wouldn't run it with boost. A modern cam ~226int will make similar top end, more down low, and be just as fast or faster while being easier to tune with better street manners.
GM847 cam on a SBE LT1 out of my camaro. This was 2006 I believe Car had LT's, CAI, Catback, Tune & Supporting mods for the cam like Springs & pushrods.
Power was nice and ran low 12's @ 113 in the 1/4, Idle was rowdy and a real head turning, After the tune adjustment from Ion (madz28) car drove flawlessly. Depending on what you want to do with the car this might not be the right cam there are plenty of cam's that can give you better power in a more streetable rpm band! as I have learned with the LS motor I have bigger is not always better. But it's your choice good luck! BTW: My motor bent rod #5 NA with that cam it was the last time I had a LT1 in the car!
Power was nice and ran low 12's @ 113 in the 1/4, Idle was rowdy and a real head turning, After the tune adjustment from Ion (madz28) car drove flawlessly. Depending on what you want to do with the car this might not be the right cam there are plenty of cam's that can give you better power in a more streetable rpm band! as I have learned with the LS motor I have bigger is not always better. But it's your choice good luck! BTW: My motor bent rod #5 NA with that cam it was the last time I had a LT1 in the car!
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Thread Starter
TECH Enthusiast
Joined: Feb 2012
Posts: 631
Likes: 0
From: Orlando
When you say Cam Only, do you really mean cam only?
Id think some rockers, better pushrods etc would be in order for that cam.
A stall converter would be need too.
Dont do a cam only install, it makes the LT community look bad.
If your going to pick a bad *** cam like the 847 put some of required goodies with it.
Id think some rockers, better pushrods etc would be in order for that cam.
A stall converter would be need too.
Dont do a cam only install, it makes the LT community look bad.
If your going to pick a bad *** cam like the 847 put some of required goodies with it.
Thread Starter
TECH Enthusiast
Joined: Feb 2012
Posts: 631
Likes: 0
From: Orlando
GM847 cam on a SBE LT1 out of my camaro. This was 2006 I believe Car had LT's, CAI, Catback, Tune & Supporting mods for the cam like Springs & pushrods.
Power was nice and ran low 12's @ 113 in the 1/4, Idle was rowdy and a real head turning, After the tune adjustment from Ion (madz28) car drove flawlessly. Depending on what you want to do with the car this might not be the right cam there are plenty of cam's that can give you better power in a more streetable rpm band! as I have learned with the LS motor I have bigger is not always better. But it's your choice good luck! BTW: My motor bent rod #5 NA with that cam it was the last time I had a LT1 in the car!
Power was nice and ran low 12's @ 113 in the 1/4, Idle was rowdy and a real head turning, After the tune adjustment from Ion (madz28) car drove flawlessly. Depending on what you want to do with the car this might not be the right cam there are plenty of cam's that can give you better power in a more streetable rpm band! as I have learned with the LS motor I have bigger is not always better. But it's your choice good luck! BTW: My motor bent rod #5 NA with that cam it was the last time I had a LT1 in the car!
ohwell it happens. 
The 847, with new bearings and upgraded rod bolts in the short block, would do decently well. I would run 1.6rr on the intake and 1.5 on the exhaust with that cam to keep the low rpm cylinder pressures up(with stock heads of course).
