Vortec Head Swap

[Chrisravosa36]

Hello Yall, I bought a 1990 Albemarle 24ft with a 350 Non-Vortec last season. Ran it all season trying to figure out why this darn thing won't go as fast as all the rest of the 24 Albemarle, and why it doesn't run as efficient. By the end of the season, I came to the realization that I need to rebuild the top end, and I think I'm going to upgrade to the Vortec style heads. I'm mechanically inclined and always work on my own trucks/boats. I've never torn apart an engine like this, but I'm not afraid to. Here is some info you for guys.


The motor is a 350 non-vortec with 450 hours. The P.O replaced the motor in 2013, with a newer cam (http://www.compcams.com/Company/CC/...ztqJl0SIXXcRbhx6Lfm4Qk7uk_aIBYt88tOyOJbCacP7k)

The P.O didn't keep up with riser gaskets when I bought the boat the risers and manifolds were on there last season, so I replaced them.

I bought a set of 90's Chevy Automotive Cylinder Heads from a truck. I had them checked for cracks and decked. I'm working on lapping the valves now and putting the seals back in. New automotive valves were put in, new seals etc. I believe my boat has stud rocker arms. and the automotive Vortec heads have screw in rocker arms, will this be an issue? or should I be alright with the Vortec screw in arms?

Also my pushrods, I recall Vortec heads had different length pushrods, so I need new ones, can anybody verify for me? Just making sure.

This afternoon I am going to start the motor up for the last time, make sure everything works as should, motor heats up and has oil pressure after the long cold winter. Il take the distributor cap off, align the rotor to the #1 cylinder on the cap, and make sure the balancer mark is aligned up with zero on the timing cover marker.

Will I have to rejet my carb? I have an Edelbrock 1409, I'm guessing I will because I'm adding about 30 ~ HP.

Now onto Rocker Arms/Springs/Valves. I am most concerned about any valves hitting cylinders... Should I go with the springs and rocker arms that were on my Vortec heads, or the old ones on my standards SBC heads? Will the CAM I have affect any of this?

Lastly, the compression ratio. With the bump in compression will I be ok with 87 or should I run 93? My 120 Gallon Tank is filled with 87 as of right now...

I know this is a lot, but I'm trying to get a perfect idea of everything I need so I can ensure everything will go smoothly (even though I know it never does) My boat is set to launch May 1st, id like to have this done April 20th so I have time to test it out a couple of days on the lake.

Let me know if you guys have any tips/tricks with a vortec swap, please let me know if the cam, heads, valves, studs, arms ect will work,

Thank you, Christopher Ravosa

 

[Scott Danforth]

I did the vortec head update years ago, and since jumped to a big block.

start with the cam specs on the cam you currently have. this will determine if you need to have your head spring pockets and guides machined. your cam dictates everything..... including which springs you must run.

I would run roller-tipped stamped rockers at 1.52:1. much higher quality than the stamped garbage from GM for very little money

I would suggest you have the heads converted to screw in rocker studs if you havent done so alread

you may have to re-jet

as for compression ratio, is your current heads 64cc or 76cc? if 64, no, you wont need to run anything other than the 87. no need to run 93. watch your base timing.

you will need to change the intake for the vortec heads

run a carb spacer. 2" cab spacer will do wonders

 

[Chrisravosa36]

I did the vortec head update years ago, and since jumped to a big block.

start with the cam specs on the cam you currently have. this will determine if you need to have your head spring pockets and guides machined. your cam dictates everything..... including which springs you must run.

I would run roller-tipped stamped rockers at 1.52:1. much higher quality than the stamped garbage from GM for very little money

I would suggest you have the heads converted to screw in rocker studs if you havent done so alread

you may have to re-jet

as for compression ratio, is your current heads 64cc or 76cc? if 64, no, you wont need to run anything other than the 87. no need to run 93. watch your base timing.

you will need to change the intake for the vortec heads

run a carb spacer. 2" cab spacer will do wonders

I believe anything below .470 valve lift will be alright for a Vortec, im at .470.

How will I benefit from the roller tips? WIll the engine run smoother or just be less noisy?
How can I tell the difference between screw in and pressed stud? The ones im upgrading to came out of a truck.
Got the new intake coming soon
A carb spacer, not sure if my engine box will be able to close properly with this, il have to check. I know the Vortec intakes are taller than standard already. What will the spacer do anyways? promote better air flow?

 

[Scott Danforth]

officially, its .420 on valve lift is the limit.

all stock vortec heads have pressed in studs. they do come out with any change of cams. a screw in stud would have a large hex at the base of the stud. google ARP rocker stud. pinning can work, however the stud usually still pulls out.

the heads you picked up will need to be re-conditioned anyway. the stock umbrella seals should be changed, and since the head is apart, 20-30 minutes with the proper cutter and your heads are ready for proper springs, seals and screw in studs.

stock stamped rockers are a 1.47:1 ratio and that actually varies between 1.44 and 1.51 from stamping to stamping.

stamped roller tipped rockers come in the 1.52:1 ratio, have a consistent geometry and reduce wear on the valve stem. all for about $20 more a set than factory stamped.

vortec intakes are no taller or shorter. the intake height is one of the variables of intakes when buying. the best intake would be one of the marine RPM performer air-gaps. this is a medium-rise intake with a divorced plenum. Make sure the intake is marine and the water passages are bronze alloy or you should be running a heat exchanger.

the carb spacer adds plenum volume which is critical for low to mid-range torque.

 

[FreeBeeTony]

I was hesitant to post this..........don't want to scare you away!
The post in the link below is my Vortec Head / Cam / Spring journey.
Should make for some interesting reading if you're interested.
Boat runs great on the hose at the moment.......haven't launched it yet this year!

https://forums.iboats.com/forum/eng...ves/10679827-vortec-head-modification-upgrade

 

[Chrisravosa36]

officially, its .420 on valve lift is the limit.

all stock vortec heads have pressed in studs. they do come out with any change of cams. a screw in stud would have a large hex at the base of the stud. google ARP rocker stud. pinning can work, however the stud usually still pulls out.

the heads you picked up will need to be re-conditioned anyway. the stock umbrella seals should be changed, and since the head is apart, 20-30 minutes with the proper cutter and your heads are ready for proper springs, seals and screw in studs.

stock stamped rockers are a 1.47:1 ratio and that actually varies between 1.44 and 1.51 from stamping to stamping.

stamped roller tipped rockers come in the 1.52:1 ratio, have a consistent geometry and reduce wear on the valve stem. all for about $20 more a set than factory stamped.

vortec intakes are no taller or shorter. the intake height is one of the variables of intakes when buying. the best intake would be one of the marine RPM performer air-gaps. this is a medium-rise intake with a divorced plenum. Make sure the intake is marine and the water passages are bronze alloy or you should be running a heat exchanger.

the carb spacer adds plenum volume which is critical for low to mid-range torque.

I've seen so many different numbers for the lift, where di you hear about .420, not trying to say that in a rude way, just trying to get an idea. I believe you. Ive seen everything from .450 - .525 max valve lift will work with a vortec, a stock vortec roller cam has over .420 exhaust valve lift

Il definitely have to upgrade to the new studs, I have new seals already, just gotta put them in. I would go with the roller tipped rockers, but I'm on a budget, and the ones I have now will work in the meantime. I saw that they are $160 at summit, a bit much for now, but a great idea for the future! I run a heat exchanger, so Im just going to run an automotive intake. Definitely going with a spacer!!

 

[Scott Danforth]

right from engine builder magazine and my old machinist that probably does 40 sets of vortec heads a week supplying the local race teams. the limit on vortec heads is anything over .420 you need to address for coil bind. It is also what GM published.

Roller tip rockers are $95 for comp cams at summit https://www.summitracing.com/parts/cca-1417-8 and less if you look around. Full roller rockers are about $200

if your on a budget, you should have bought a set of vortec heads with all the upgrades already done for $400 from racingjunk.com or your local circle track racers

 

[Scott Danforth]

Make sure you read this thread that Lou posted in your THT thread back in January https://forums.iboats.com/forum/eng...ves/10679827-vortec-head-modification-upgrade

 

[Chrisravosa36]

right from engine builder magazine and my old machinist that probably does 40 sets of vortec heads a week supplying the local race teams. the limit on vortec heads is anything over .420 you need to address for coil bind. It is also what GM published.

Roller tip rockers are $95 for comp cams at summit https://www.summitracing.com/parts/cca-1417-8 and less if you look around. Full roller rockers are about $200

if your on a budget, you should have bought a set of vortec heads with all the upgrades already done for $400 from racingjunk.com or your local circle track racers

Gotcha, so here is what I need to do correct?

1. Have the machine shop cut into the head and make a spring pocket, how much do I need them to cut? Exhaust valves are .467 and intakes are .447, so does that mean I need to cut aprox. .027 off the intake valve spring pockets, and .037 off the exhaust spring pockets?

2. Order a set of screw in studs and install those

Will cutting into the head allow me to use stock springs, or should I just go with all new equitment, rockers, springs, studs ect.

 

[Scott Danforth]

you need to get the correct springs from Comp to match the cam.

spring pockets are cut to the depth needed per the comp cam spring. the same cutter also trims the valve stem for the new seals. normally this is about $50 at my machine shop.

you then need to have various shims to get the spring installed height dialed in. you use checking springs. (I have a pile of light springs from Ace Hardware and use a dial caliper)

the stock spring will not have enough spring pressure. so you need new springs. there are recommended springs for each cam. They will have a minimum seat pressure to ensure you dont float the valves. if you update the keepers (7 degree vs 10 degree), you also need new locks. again, the cam and spring determine this

regarding the thread in studs, you need to have the head machined for thread in studs. Normally this is about $50 at my machine shop. then the stud length is based on the rocker style. Normally your machine shop will have studs in stock for the same price or less than you can get on-line yourself.

 

[Chrisravosa36]

you need to get the correct springs from Comp to match the cam.

spring pockets are cut to the depth needed per the comp cam spring. the same cutter also trims the valve stem for the new seals. normally this is about $50 at my machine shop.

you then need to have various shims to get the spring installed height dialed in. you use checking springs. (I have a pile of light springs from Ace Hardware and use a dial caliper)

the stock spring will not have enough spring pressure. so you need new springs. there are recommended springs for each cam. They will have a minimum seat pressure to ensure you dont float the valves. if you update the keepers (7 degree vs 10 degree), you also need new locks. again, the cam and spring determine this

regarding the thread in studs, you need to have the head machined for thread in studs. Normally this is about $50 at my machine shop. then the stud length is based on the rocker style. Normally your machine shop will have studs in stock for the same price or less than you can get on-line yourself.

One question I have, the P.O put this cam in the current engine, im wondering if he didn't have the correct springs or cut any of the pockets? I know he had pressed in studs, and non-roller rockers. Can a non-vortec head take more lift than a vortec one?

 

[Chrisravosa36]

If you look at my cams specs. and go where it says recommended components you can see the {7} which corresponds to me required to get new valve springs and do machining. There are two style springs suggested for my cam, beehive springs and Single Outer Valve springs, which one should I get, Beehives are twice the price!!

 

[Scott Danforth]

Yes, many of the heads had more lift capacity than a Vortec head. However since you need to freshen the heads up anyway, get the traditional single spring and have the heads machine

 

[Scott Danforth]

However after Machining the vortec heads will be just fine

 

[Chrisravosa36]

However after Machining the vortec heads will be just fine

Alright, Here is my action plan.

Order the springs, I have to call comp cams and ask them how much is needed to be taken off the cylinder head to get them to fit right

Bring them down to the machine shop and have them cut the spring holes and do the rocker studs.



Im hoping all of this doesnt cost more than $300, but we will just have to see.

 

[Scott Danforth]

if your machine shop is any good, you can simply take the heads to them, tell them what you want, and they most likely have the parts in stock for less money than you can order, and they already know what they need to cut the heads to.

 

[Chrisravosa36]

if your machine shop is any good, you can simply take the heads to them, tell them what you want, and they most likely have the parts in stock for less money than you can order, and they already know what they need to cut the heads to.

Sounds good, il call a few and see what they want to do the job. I live in MASS, so everything is crazy expensive here, we will have to shop around lol.

 

[Chrisravosa36]

if your machine shop is any good, you can simply take the heads to them, tell them what you want, and they most likely have the parts in stock for less money than you can order, and they already know what they need to cut the heads to.

Just called my machine shop, only $250 for them to put studs in and pocket the springs, he just wants to know how much we need to take off the heads.

I called comp cams and he said the absolute max lift on a Vortec head is .480 and that I should have no problem putting a set of Single Outer Valve Springs: 1.254" springs on the heads. He said I shouldn't have a problem with coil bind. Now I'm confused.

 

[Scott Danforth]

From my understanding, the .480 is with the beehive springs. however I could be wrong. everything I see says .420, with one reference to .450 (on the Scoggin Dickey site)

direct cut-n-paste - Furthermore, the OE-production Vortec valvetrain requires a self-guided rocker system that will not exceed a maximum valve lift of 0.420 inches unless the valvetrain has been modified.

find a different machine shop. $250 is about what I paid to have a 5-angle valve job, convert to studs, get the studs and have the pockets cut for new springs and have the machine shop flow-test both heads and assemble them.

FYI - you can buy brand new heads modified by Scoggin Dickey for $680 each https://sdparts.com/i-23901396-sdpc...der-head-with-0-525-valve-spring-upgrade.html that is not much more than a brand new GM head

 

[Chrisravosa36]

From my understanding, the .480 is with the beehive springs. however I could be wrong. everything I see says .420, with one reference to .450 (on the Scoggin Dickey site)

direct cut-n-paste - Furthermore, the OE-production Vortec valvetrain requires a self-guided rocker system that will not exceed a maximum valve lift of 0.420 inches unless the valvetrain has been modified.

find a different machine shop. $250 is about what I paid to have a 5-angle valve job, convert to studs, get the studs and have the pockets cut for new springs and have the machine shop flow-test both heads and assemble them.

FYI - you can buy brand new heads modified by Scoggin Dickey for $680 each https://sdparts.com/i-23901396-sdpc...der-head-with-0-525-valve-spring-upgrade.html that is not much more than a brand new GM head

Gotcha, so I should have ordered the beehive springs? My machine shop asked me how much is needed to be cut, and that I should call the Cam company, and I called them and they said nothing has to be cut? Im stuck here, I want to have it done the right way, and Scott, what you are saying makes perfect sense to me! $250 was the least expensive, I live in Mass, everything is a rip off here...