[ExcellenceAuto]

Here is the 264 cam Bogie was speaking of.

COMP Cams XR264HR Dyno Results

Dyno Results for Chevrolet 350 Small Block XR264HR-10

www.compcams.com

It will make better power than stock.

Or this one.

COMP Cams XR276HR Dyno Results

Dyno Results for Chevrolet 350 Small Block XR276HR Camshaft

www.compcams.com

This one will have a choppy idle, and I have used it in a pretty much stock L31 and it ran really, really well.
Pushed my 4000 pound truck down the 1/4 in 13.5 seconds.

Since you are changing the springs, these could both be an option.

The bigger cam will be close with beehives.
And for what it's worth, I used stock rockers and pushrods with mine.
Again, Bogie is more familiar with exactly what needs to be done, but from what I gather you can achieve this with beehives. And he really has had good results with the 264. The GM Hotcam is always any option too. I think that 276 grind is very similar.

I'm just thinking in the future, when your car is together. I don't want you to say "I wish it has a little more power, I should have put a cam in it while it was apart..."

 

[35olds]

Thank you , ExcelenceAuto , I will look into the XR276 , with beehive springs . Stock rockers ,appreciate it ,
Bob

Here is the 264 cam Bogie was speaking of.

COMP Cams XR264HR Dyno Results

Dyno Results for Chevrolet 350 Small Block XR264HR-10

www.compcams.com

It will make better power than stock.

Or this one.

COMP Cams XR276HR Dyno Results

Dyno Results for Chevrolet 350 Small Block XR276HR Camshaft

www.compcams.com

This one will have a choppy idle, and I have used it in a pretty much stock L31 and it ran really, really well.
Pushed my 4000 pound truck down the 1/4 in 13.5 seconds.

Since you are changing the springs, these could both be an option.

The bigger cam will be close with beehives.
And for what it's worth, I used stock rockers and pushrods with mine.
Again, Bogie is more familiar with exactly what needs to be done, but from what I gather you can achieve this with beehives. And he really has had good results with the 264. The GM Hotcam is always any option too. I think that 276 grind is very similar.

I'm just thinking in the future, when your car is together. I don't want you to say "I wish it has a little more power, I should have put a cam in it while it was apart..."

AND , you did not machine the heads for this .510 lift ?

 

[35olds]

Thank you , ExcelenceAuto , I will look into the XR276 , with beehive springs . Stock rockers ,appreciate it ,
Bob

AND , you did not machine the heads for this .510 lift ?

Thank you , ExcelenceAuto , I will look into the XR276 , with beehive springs . Stock rockers ,appreciate it ,
Bob

AND , you did not machine the heads for this .510 lift ?

I've never used Behive springs before , can you use the stock retainers with these springs ?
I've only built stock 283 and 327 engines , this vortec will be the first modern engine ., Bob

 

[BogiesAnnex1]

I've never used Behive springs before , can you use the stock retainers with these springs ?
I've only built stock 283 and 327 engines , this vortec will be the first modern engine ., Bob

No the retainers you need are Comp part number 787-16. These are made to secure the beehive spring to the 11/32nds diameter of the Chevy valve stem used in the L31 head and older Chevy head’s accepting the standard Chevy 7 degree lock.

A little history is where Chevy went to an 8mm metric size valve stem with the Gen III engines. Most retainers sold are for this valve stem diameter that also fit the top of the beehive spring. When or if these retainers are used on older heads with the 11/32 valve stem and any beehive spring the 11/32nd locks do not seat properly in the retainer and they will be seen as sitting higher than the top surface of the retainer. This is subtlety higher, it doesn’t reach out and grab you by the throat so this is something the hobby engine assembler is likely to miss thinking all is OK till one day a valve falls into a cylinder.

So again for the SBC’s using 11/32nd valve stems which is historical up through the L30 and L31 engines when switching to beehive springs you want to use Comp’s 787-16 retainers with standard Chevy SBC 7 degree locks.

Bogie

 

[55_327]

To elaborate on Bogie's post about installing beehive valve springs on Vortec heads, here are my notes from 2016:

LS6/LS2 springs
GM 12499224 (blue)
Set of 16: $61
OD: 1.20”
Spring rate: 375#
Installed Height (GM spec): 90# @ 1.800, 126# @ 1.700
Open Pressure: 295# @ 1.250, 314# @ 1.20”
Max Lift: 0.570"
Top ID: .650”
Top OD: 1.055”

Retainers and locks for LS spring ID and Vortec 11/32” valves
I installed the springs @ 1.750” with approx 110# pressure
Comp 787-16 retainers: $52 (Allows for .050" more installed height than stock Vortec retainers)
Comp 648-16 locks: $24

I don't have notes on max safe lift, but as I recall it was around .510" with springs installed @ 1.750".

I used a RamJet 350/HT383 cam ($120 new take-out) in a 355 with approx 9.5:1 compression. However, based on later comments by Bogie, it probably wasn't the best choice. I also used a Weiand #8121 intake with a #80457SA 600 cfm Holley carb. Pretty decent combo especially in a pickup with a 2.73 axle!

 

[ExcellenceAuto]

No the retainers you need are Comp part number 787-16. These are made to secure the beehive spring to the 11/32nds diameter of the Chevy valve stem used in the L31 head and older Chevy head’s accepting the standard Chevy 7 degree lock.

A little history is where Chevy went to an 8mm metric size valve stem with the Gen III engines. Most retainers sold are for this valve stem diameter that also fit the top of the beehive spring. When or if these retainers are used on older heads with the 11/32 valve stem and any beehive spring the 11/32nd locks do not seat properly in the retainer and they will be seen as sitting higher than the top surface of the retainer. This is subtlety higher, it doesn’t reach out and grab you by the throat so this is something the hobby engine assembler is likely to miss thinking all is OK till one day a valve falls into a cylinder.

So again for the SBC’s using 11/32nd valve stems which is historical up through the L30 and L31 engines when switching to beehive springs you want to use Comp’s 787-16 retainers with standard Chevy SBC 7 degree locks.

Bogie

Bogie, will he be able to squeeze 0.510 lift with just beehives, or is that cutting it too close?
If not, what are your thoughts on the GM Hotcam for his application?

 

[35olds]

Bogie, will he be able to squeeze 0.510 lift with just beehives, or is that cutting it too close?
If not, what are your thoughts on the GM Hotcam for his application?

Thanks again Bogie , I appreciate everone here ! Bob

 

[55_327]

On Comp's dyno charts, I see where the XR 276 makes the same amount of TQ as the XR 264 at low RPMs. I'm not sure I'm buying that. Maybe it's their FM grind.

 

[35olds]

Thanks 55_327 for the part numbers , Bob

 

[BogiesAnnex1]

The GM blue beehive is good on the LT4HOT cam with a 1.6 rocker. The spec max lift installed at 1.8 height which is stock Chevy install height says this is good for .550 inch lift which exceeds the HOT cam with a 1.6 rocker by .025 inch.

Coil bind is at 1.220 for coil bind so 1.800 minus .525 of the HOT lobe with a 1.6 rocker gives 1.275 inch height at max lift leaving a comfortable margin of .055. Generally .050 inch of total coil loops freedom is considered the tight side limit.

My personal favorite with the LT4HOT cam is the Howard’s HRC98114 electro polished beehive which coil binds at 1.15 so it buys a little extra space if you like to wind out the motor for not a lot more money, but their are many other excellent choices in the market place.

Bogie

 

[35olds]

Thanks again Bogie , just got the 350 home last night .

 

[35olds]

Block cast'g. 10246880 , made in Mexico , I cannot find any info on this block , I will start tearing it down and report here the heads cast'g numbers ,I'll go with a normal water pump .

 

[95 Truck]

I believe 880 is from 96 or so, possible 4 bolt main.

 

[35olds]

I believe 880 is from 96 or so, possible 4 bolt main.

My bet is that it will be a 4 bolt, it came out of a big four wheel drive truck.

 

[BogiesAnnex1]

Check the head’s is this is from 3/4 ton or heavier duty 4x4 it might have 906 heads and possibly rotators and 3/8 stems on the exhaust valves. Not all 906 head’s are so equipped but as you get further into trucks intended to work for a living these items become more common not always there but require some different rework if you go into the head’s than do 062’s or I guess what you might think of as a medium duty 906. The 906 head is almost always equipped with pressed in exhaust hard seats rather than induction hardened seats.

The 062 head is more given to cracking and given the troubles that GM had with DexCool that lead to coolant loss and subsequent overheating it is worth your time to check this out before stuffing the engine into something then discovering it leaks coolant inside the motor.

Bogie

 

[35olds]

Thanks for that Bogie ,something else to worry about, LOL , I'll pull the valve covers off soon and get back to you ,Bob

 

[35olds]

Thanks for that Bogie ,something else to worry about, LOL , I'll pull the valve covers off soon and get back to you ,Bob

I just looked Bogie , they are 906 heads , all the pushrods are the same diameter .

 

[35olds]

Another thing I have noticed on the damper there is a timing line, could this damper be used? Thanks Bogi
I just looked again and all the valves are the same size , looking at the to just above the keepers .

 

[BogiesAnnex1]

Push rods would be all the same diameter, that should be a roller cam motor so they will be the shorter 7.2 inch length. Flat tappet uses 7.8 inch push rods. This adjusts for the taller roller lifter.

The valve stems all the same size says these are 11/32 standard Chevy valves. You would have to take the head’s off and the valves out to see if these are induction hardened or hard inserts on the exhaust side which in the big picture doesn’t matter in terms of just using them short of racing those heads. The hard insert heads don’t flow on the exhaust side quite as much as the induction seat, it’s a very small difference but drives racers into cleaning the blend of the insert seat to the casting.

Certainly are clean inside and ma shows this is probably a low mileage crate motor or are replacement heads.

Bogie

 

[35olds]

I was surprised at how clean the heads were as well .This could have been a fleet truck and the oil was changed regularly . I think I'll use the damper and get a correct bolt on timing marker . This is going to be a neat project for me .
Thanks Bogie This engine sounded very healthy running . It was a tough pull out .