Starting to try and come up with a game plan for the new truck and am trying to understand the different ratio roller rockers and how different ratios affect certain things.

Truck is 2004 Silverado with a stock 5.3 right now. Will be putting the D1 from my 2011 on it along with most the supporting mods. I will have another custom speced cam done once I decide what stall and gears i will be running.

My question is what's the difference or gains/losses between a 1.7 ratio and a 1.8. I had Yella Terra 1.8's on my 2011 so will probably go with Yella Terra again, just not sure how to determine what ratio is best.

Did a quick search and didn't really see any threads dedicated to this but if I missed it please point me in that direction.


Thanks.

 

Just do a trunnion kit up grade to the 1.7 (stock'ers) and be done. The 1.8 are not any gain what so ever over the 1.7. I dynoed both with a HT1 cam (214/218 .559/.562 111lsa) in a 5.3 and nothing changed but my wallet was a lot lighter. plus the 1.8 needed the valve cover spacer and was really tight to fit in the head and the swipe in the valve stem changed. I ran Harland sharp.

 

You hit a point of diminishing returns with lift and stock heads.

If it were me, I'd probably run the YT 1.7s and spec the cam with the lift I wanted. In fact, thats what I'm doing.

The only issue known to me with 1.8s depends on the cam. They don't work well with a high ramp rate cam.

 

With all the cam lobes available my feeling would be the same as above... If you want more lift of more aggressive ramp rate then choose a lobe that will deliver that for you.

I dont have any first hand results to back that up... but thats my initial feeling about it.

 

Thanks for the responses. Got to looking into it more and thinking I will just jump straight to a 6.0 and build what I really want instead of starting with the stock 5.3 that's in there now.

I'm sure this is subject to change but right now after talking with Roger I think this would be a pretty nasty combo.

Get a 6.0 and go .030 over, forged pistons/rods, my cam and pick up some L92/LS3 heads and put my springs, pushrods and rockers on those. Back that up with the D1 and should be a pretty mean setup, plus I am reusing a lot of the parts I have already bought.

If all goes well will be a busy winter.

 

Sounds awesome Andy. You're gonna have some fun!

What did you decide to get to replace the truck?

 

2004 Silverado RCSB 2wd 5.3
https://www.performancetrucks.net/fo...-gibbs-519496/
Was going back and forth on if I should mod the 5.3 and see how it does or just start with a 6.0 and go forged from the get go. Leaning towards the 6.0 like mentioned above.

 

Looks like it will be a fun build, try not to blow this one up!

 

Really hoping I don't LOL.

Although that was one of the big factors into getting this truck. It's paid for, if I break it, blow it up, cut it in half in a fit of anger.....I can push it into the garage and get to it at my own pace.

It hurts having a very expensive truck, broken in the shop, not being used and still making monthly payments on it. Plus I really got to thinking and I really don't need a crew cab truck. Wife has an SUV that's 4x4 so we are covered on the family rig year round. Plus the heaviest thing I ever hauled with my truck was garbage to the dump, hardly justifies the truck I bought.



YAY impulse buys!


Really looking forward to building this new truck and doing as much work as I can myself. Get a engine stand/hoist, get any tools I am missing, learn as much as I can and really get into it.

Also learning how much needs to be upgraded to handle my future power goals. Fuel system, trans, drive line.. etc etc etc. LOL

 

Like the truck a lot. Very clean.

I also like the direction you're going.