sparky24

Thinking about switching to full roller. Got a couple of questions.

1. What do i need to retrofit into a gen v block?

2. Are the lifter bores going to be a problem? Do they need to be checked, aligned, and have bushings installed?

3. Are there high quality roller lifters i can get for under 500 dollars?

4. If i just want reliable 450-470 horsepower from my freshened 420 mag (YES i already have stainless marine exhaust, holley 800, rectangular port heads, etc, etc.) DO i REALLY need roller?

5. Are full roller setups LESS reliable than a flat tappet setup?

f_inscreenname

1. What do i need to retrofit into a gen v block?
You will need roller lifters with the tie bars, roller rockers and longer studs, roller cam and cam button, maybe a timing chain cover

2. Are the lifter bores going to be a problem? Do they need to be checked, aligned, and have bushings installed?
Not on the last two I have done but to each their own

3. Are there high quality roller lifters i can get for under 500 dollars?
Yes, especially for under 500hp but I naming names just to get flamed

4. If i just want reliable 450-470 horsepower from my freshened 420 mag (YES i already have stainless marine exhaust, holley 800, rectangular port heads, etc, etc.) DO i REALLY need roller?
Ever little bit helps but for the money the hp is not cheap

5. Are full roller setups LESS reliable than a flat tappet setup?
I will say no

sparky24

I basically built my motor from a build sheet that i saw you post somewhere on here. Right now i have a crane 132561 the mercruiser 420 cam. I have a double timing chain with cam button in it which preloads against the timing chain cover. If i stay flat tappet people are telling me to be very careful with the tappets, i have been recommended delphi tappets.

Did you check your lifter bores? or just go with it

some good info in this thread: http://www.performanceboats.com/dyno...lifters-5.html

Griff

You need

Roller Cam
Retro fit roller lifters
Different Timing chain set
Valve Springs with correct spring pressure
Roller Rocker arms

PowerAddict

valve spring pressure is important, there are some charts that have some good rules of thumb. mine are something like ~175lb seat pressure and around 385-400 over the nose (but will vary per cam manufactuer - also, if you are going solid roller, even stiffer pressures are usually required). This is to keep the valve in place with the higher ramping rate of the roller cam lobe profile

You will also need to measure for new pushrods because the roller lifters are taller than the flat tappets, so added to the list:
-Push rod length checking tool
-Valve spring removal tool
-The light weight valve springs (to go in place of valve springs when checking push rod length)
-Pushrods
-Also, if you don't currently have roller rockers, and you are running stock valve covers, you will either need new valve covers, valve cover spacers, or, run two valve cover gaskets (the latter is what I did, I RTV'd them together a day ahead of time before install)


But you can definately find roller lifters for less than 500, I got mine for less than 200 (used ofcourse, but they're a good unit). Be careful of the new cheap junk on eBay.

Griff

All you need to do to run stock Merc valve covers with run roller rockers is cut off the drip tabs on the underside of the valve covers.
You will need new pushrods also as said.above.

I would never put used roller lifters in to save a few hundred $$$. If one breaks, it can destroy the entire engine.