rocker arm ratio

[WS6]

Been searching for awhile tonight and I can't get a conclusive answer for what the TTA stock rocker arm ratio is. I've found references to 1.55,1.60 and 1.70.

Anyone have a definitive answer or maybe we can get a consensus on them.




....

 

[JP112_89]

..

Pretty sure they are 1.55 I bet you could call Harland Sharp and they could help you out. I am sure Julio knows as well.

 

[Razor]

My understanding was 1.7's

Buicks where the 1.6's

Just keep in mind overall valve lift when choosing the rocker. As it affects springs and coil bind issues with the springs available.

Having to redo things today, i'd do the 1.6's on the TTA.

 

[WS6]

Just keep in mind overall valve lift when choosing the rocker.

That's what I'm after, but rather picking a cam based on the stock rocker ratio.

 

[89ICBM]

Been searching for awhile tonight and I can't get a conclusive answer for what the TTA stock rocker arm ratio is. I've found references to 1.55,1.60 and 1.70.

Anyone have a definitive answer or maybe we can get a consensus on them.


Hi WS6,

This is, as is commonly said, spliting hairs but, the actual ratio is 1.67. If you are going to change cams and rocker arms, I totaly agree with razor and you should go with a 1.6 not a 1.7. The lift is, of course, decided by the cam and to a certain degree, the rocker ratio. If you go to a larger lift cam you will need to change the length of the push rods. Now, this may sound more technical than it really is. The cam you get will have different info with it. Some times it will give the lift at the lobes, other times, when you order the cam, the vendor will ask you what your rocker ratio is. When the later is asked, your cam sheet or card will give you the over all lift, if the sheet gives lobe lift, just multiply the rocker ratio times the lift and that will give you over all. I again agree with razor that you have to be careful with lift. With the stock valve covers you are dealing with a limited space.

 

[JP112_89]

..

I went with the 1.6 from Harland Sharp. You will need to send your studs to Harland Sharp to be modified. If you go roller, than I would definitely buy them because of the higher spring pressure. $375 shipped wasn't that bad IMO

 

[Scott89TTA]

I have a question regarding the Harland Sharp roller rockers. I have a complete set ready to go (modified studs) for the TTA that I purchased from JD (jdsgnx) a while back. Is there any performance gain to install them now with my stock cam? My plan was to install them when I installed a roller cam but that may be a while. If there is even a small benefit I will put them in over the Winter.

Thanks,
Scott

 

[80/89TTA]

I have recently just talked to Harland Sharp about TTA Rocker Arms - Randy Becker - R&D at Harland Sharp - Factory Ratio is 1.55.

 

[JP112_89]

Is there any performance gain to install them now with my stock cam? My plan was to install them when I installed a roller cam but that may be a while. If there is even a small benefit I will put them in over the Winter.

Thanks,
Scott

Friction reduction is one benefit. Another benefit of roller rockers include true, blueprinted, at-the-valve ratios and precision motion. FYI, increasing the rocker ratio improves engine performance by opening the valves faster and further. The combined benefits of reduced friction and improved airflow can increase hp. Just guessing, I would guess 5 hp.

 

[Scott89TTA]

Friction reduction is one benefit. Another benefit of roller rockers include true, blueprinted, at-the-valve ratios and precision motion. FYI, increasing the rocker ratio improves engine performance by opening the valves faster and further. The combined benefits of reduced friction and improved airflow can increase hp. Just guessing, I would guess 5 hp.

yeah...I figured all that...don't know why I didn't look into it more while I had everything apart doing the head gaskets

I believe I can use the stock push rods as well...correct? and also what about my 100# valve springs?

I assume that by increasing the ratio from 1.55 to 1.6 would add a little more lift to the stock cam as well...if so that couldn't hurt either

Scott

 

[YamikidR1]

look at what came today! along with a port intake and a few other goodies

Sorry havent master the art of resiziing pics

 

[JP112_89]

I believe I can use the stock push rods as well...correct? and also what about my 100# valve springs?
Scott

Your stock push rods will work. I'm using the Comp 941's so.. your be fine.:biggrin:

Ditch those old rattling heavy steel rockers:biggrin: Congrats again on your new times Scott!

 

[Scott89TTA]

new parts look awesome...can't wait to get my heads done too!!!


-Scott

 

[BandAid]

high lift roller cam ,Harland Sharp Rockers (1.7) custom pushrods and not clearance problems in my Valve covers,,but i have 2 drivers VC's...at 10psi it feels like some of my GN's at 22psi..go figure...