Centerbolt heads and HSR
Thread Starter
Senior Member
Joined: May 2006
Posts: 529
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From: Bartlesville, OK
Car: 2011 Cummins HO
Engine: 350 HSR
Transmission: T-56
Axle/Gears: 3.43
Centerbolt heads and HSR
I was planning on re-using the 58cc chambered heads (081 castings?) from my 305 motor on the 350 I am building but tearing down the old motor has left a header bolt and 1 and a half spark plugs in there (mostly corrosion). Of course, the more of these things happen, the more expensive it is going to be to re-use the old heads..
As a result, I have been looking into aftermarket heads and found these Trick Flow heads will work with the center bolt style TPI intake i have now.. What I want to be sure of though is that I am not restricting myself such that in the future I would not be able to run an HSR with these heads? If so, do I get the regular HSR or the one for Vortec heads?
My original plan was to re-use the 305 heads and intake then as time/money permits, upgrade the heads and intake together, that way I wouldnt need to worry about the heads being suitable for center bolt style intakes.
Can anyone help with my question as this may sway me in the direction of the aftermarket heads instead of throwing money away on the old Iron 305 heads.
Any other suggestions are welcome also..
As a result, I have been looking into aftermarket heads and found these Trick Flow heads will work with the center bolt style TPI intake i have now.. What I want to be sure of though is that I am not restricting myself such that in the future I would not be able to run an HSR with these heads? If so, do I get the regular HSR or the one for Vortec heads?
My original plan was to re-use the 305 heads and intake then as time/money permits, upgrade the heads and intake together, that way I wouldnt need to worry about the heads being suitable for center bolt style intakes.
Can anyone help with my question as this may sway me in the direction of the aftermarket heads instead of throwing money away on the old Iron 305 heads.
Any other suggestions are welcome also..
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From: Kissimmee, FL
Car: 1991 Camaro RS
Engine: 357cid
Transmission: T5 Swap
Axle/Gears: 10bolt 7.5" 3.23 soon to be 3.73
Re: Centerbolt heads and HSR
dont use the 305 heads.... the combustion chamber of the 305 heads is much smaller than the 350 heads in relation to the smaller bore of the 305 its just not a good idea... as well as the 305 heads will flow like crap
Joined: Jul 1999
Posts: 10,950
Likes: 26
From: Orange, SoCal
Car: 1990 Pontiac Trans Am
Engine: 355 TPI siamesed runners
Transmission: Tremec T56
Axle/Gears: 12-Bolt 3.73
Re: Centerbolt heads and HSR
Get the regular Stealth Ram for those Trick Flow heads. They are one of the best heads available for our cars. You are making a great choice.
Thread Starter
Senior Member
Joined: May 2006
Posts: 529
Likes: 0
From: Bartlesville, OK
Car: 2011 Cummins HO
Engine: 350 HSR
Transmission: T-56
Axle/Gears: 3.43
Re: Centerbolt heads and HSR
Thanks guys, the other reason for re-using the 305 heads was compression ratio. I bought a new GM short block which came with dished pistons so using the iron heads would of brought my compression up to about 9.1 or so i think, using those Trick Flow aluminium heads with larger combustion chambers is going to decrease my CR down to 8.4 iirc - pretty low..
I dont have the money right now to do everything i want to but my plan was to possibly replace the pistons with some flat tops when i got new heads/intake.. I am thinking though that if i use the TPI intake for now, the lower CR shouldnt be such a big issue as i should still produce a good amount of torque (street car), and i will just replace the pistons if/when i ever save up enough to get an HSR.
I dont have the money right now to do everything i want to but my plan was to possibly replace the pistons with some flat tops when i got new heads/intake.. I am thinking though that if i use the TPI intake for now, the lower CR shouldnt be such a big issue as i should still produce a good amount of torque (street car), and i will just replace the pistons if/when i ever save up enough to get an HSR.
Joined: Jul 1999
Posts: 10,950
Likes: 26
From: Orange, SoCal
Car: 1990 Pontiac Trans Am
Engine: 355 TPI siamesed runners
Transmission: Tremec T56
Axle/Gears: 12-Bolt 3.73
Re: Centerbolt heads and HSR
I'd suggest waiting and saving up the money to do the job once, and do it right the first time. It stinks having to do the same work twice, later.
Thread Starter
Senior Member
Joined: May 2006
Posts: 529
Likes: 0
From: Bartlesville, OK
Car: 2011 Cummins HO
Engine: 350 HSR
Transmission: T-56
Axle/Gears: 3.43
Re: Centerbolt heads and HSR
Thanks for the advice but thats really not an option for me.. The only thing keeping me going right now is the thought of building this motor and being able to drive a stick again.
The car is back to being a shell right now, I have just about finished replacing the entire floor pan, and still have a quarter panel to go.. I have never done anything anywhere near this major before and I have discovered that I do not have a fond liking for metal work/body work..
The motor will be the first time i have ever torn into a motor at all, let alone a V8 so if/when i have to do it again, it will be a much more welcomed experience than having to do more body work. And an added bonus will be that any mistakes I make first time around, I should be able to correct the second time around.
The point of the thread was really to just see if people thought that these additional problems with my old heads would make re-using them cost prohibitive.. I had planned on spending as little as possible on them (money is tight) as well as having the thought of buying aftermarket heads sometime down the road - If i buy new heads now, it will wipe out most all of my remaining budget, but if the cost of re-using the old heads starts getting too steep, it will be worth just buying new heads..
The car will by no means be a DD, more a nice weather weekend car that might see the occasional track day (road course not drag strip).. so top end power is not a high priority, more interested in torque low down..
The car is back to being a shell right now, I have just about finished replacing the entire floor pan, and still have a quarter panel to go.. I have never done anything anywhere near this major before and I have discovered that I do not have a fond liking for metal work/body work..
The motor will be the first time i have ever torn into a motor at all, let alone a V8 so if/when i have to do it again, it will be a much more welcomed experience than having to do more body work. And an added bonus will be that any mistakes I make first time around, I should be able to correct the second time around.
The point of the thread was really to just see if people thought that these additional problems with my old heads would make re-using them cost prohibitive.. I had planned on spending as little as possible on them (money is tight) as well as having the thought of buying aftermarket heads sometime down the road - If i buy new heads now, it will wipe out most all of my remaining budget, but if the cost of re-using the old heads starts getting too steep, it will be worth just buying new heads..
The car will by no means be a DD, more a nice weather weekend car that might see the occasional track day (road course not drag strip).. so top end power is not a high priority, more interested in torque low down..
Member
Joined: Sep 2004
Posts: 381
Likes: 1
From: Bement IL, Champaign,IL
Car: 1985 IROC-Z Silver
Engine: Vortec 5.7L
Transmission: WC-T5
Axle/Gears: 3.23 disc brake 10 bolt
Re: Centerbolt heads and HSR
EXACTLY DUDE! The second merry go round is much easier... If keep ur cool, dont throw wrenches, and take a break when ur about to break something or throw something, it can be quite fun and done very efficiently. It doesnt have to be "WORK". This is why I love my 90 Mustang GT. I can do a Motor swap, tranny, swap, top end, whatever, in a DAY.
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Back to topic....Use the 305 heads for now... Just throw them on with the TPI. Save ur cash, then do the heads and stealth ram at the same time.
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Back to topic....Use the 305 heads for now... Just throw them on with the TPI. Save ur cash, then do the heads and stealth ram at the same time.
Last edited by z28freak84; Jan 19, 2009 at 05:10 PM. Reason: Automerged Doublepost
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Thread Starter
Senior Member
Joined: May 2006
Posts: 529
Likes: 0
From: Bartlesville, OK
Car: 2011 Cummins HO
Engine: 350 HSR
Transmission: T-56
Axle/Gears: 3.43
Re: Centerbolt heads and HSR
So it shouldnt be too much work for a machnie shop to get the old bolt and spark plugs out?
Thread Starter
Senior Member
Joined: May 2006
Posts: 529
Likes: 0
From: Bartlesville, OK
Car: 2011 Cummins HO
Engine: 350 HSR
Transmission: T-56
Axle/Gears: 3.43
Re: Centerbolt heads and HSR
One other thing, how do I know which pushrods to get? I think i am set on getting the Trickflow heads and already have some 1.6 Full roller rockers - I know the best way to figure it out is with a pushrod length checker, but I have seen the pushrod length can be anywhere from 7 - 8 inches and the length checkers I have seen dont tend to be THAT adjustable.. They are either 6.5 - 7.5 or 7.5 - 8.. Do i just need to get 2 length checkers or does anyone know a ballpark for where i should be at in terms of pushrod length?
Thanks,
Richard.
Thanks,
Richard.
Joined: Jul 1999
Posts: 10,950
Likes: 26
From: Orange, SoCal
Car: 1990 Pontiac Trans Am
Engine: 355 TPI siamesed runners
Transmission: Tremec T56
Axle/Gears: 12-Bolt 3.73
Re: Centerbolt heads and HSR
Roller cams and lifters use pushrods that are around 7.200" long.
Flat-tappet cams and lifters use pushrods that are around 7.800" long.
What length checker you need depends on what type of camshaft you're using.
Flat-tappet cams and lifters use pushrods that are around 7.800" long.
What length checker you need depends on what type of camshaft you're using.
Thread Starter
Senior Member
Joined: May 2006
Posts: 529
Likes: 0
From: Bartlesville, OK
Car: 2011 Cummins HO
Engine: 350 HSR
Transmission: T-56
Axle/Gears: 3.43
Re: Centerbolt heads and HSR
So the main factor in pushrod length is the lifter type... Every day's a school day
Joined: Jul 1999
Posts: 10,950
Likes: 26
From: Orange, SoCal
Car: 1990 Pontiac Trans Am
Engine: 355 TPI siamesed runners
Transmission: Tremec T56
Axle/Gears: 12-Bolt 3.73
Re: Centerbolt heads and HSR
You're beyond me now. Hopefully someone else who builds engines will step in here.
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