What valve springs & lifters to use on 06 Merc 496 mag with BP 203 cam & roller rocks
 

Hi as the title says I'm looking for suggestions and part #'s of which valve springs to use on a stock 2006 Merc 496 mag engine that I'm going to be installing a Raylar BP 203 camshaft and Raylar roller rockers on. I understand that the stock valve springs are 90# springs and it's recommended to go with a stronger valve spring with this cam 120# ? Please let me know which valve springs I should use with part #s as well as if I should also replace the lifters? The engine has 150 hours on it verified with Merc scan tool. I'm also trying to decide between the Whipple stock 496 HO ECU program or their stage 1 program? Any suggestions on that would be deeply appreciated as well.

Thanks in advance for your advice and suggestions.

Give Larry @ Raylar a call. He has everything you need. You need to upgrade the stock valvesprings. If the stock lifters look good/roll freely they are fine to reuse. You'll be hard pressed to find a better lifter. I am running the Whipple Stage 2 tune. Very pleased with every aspect of it. I am also running Raylar's rockers. Very nice parts. Do you plan on monitoring your air/fuel ratio? Running with stock fuel pressure?

Hi I have spoke to Larry a couple of times and he doesn't sell the valve springs any longer and couldn't provide me with a part number. I did order an adjustable fuel pressure regulator from him when I ordered the 203 cam and roller rockers so I will be upgrading that as well. Great on the lifters as the motor has been gently used with over 50 of the hours at idle rpm, so I would imagine that the engine internals should look very good once it's opened up. The cost will be the same either way for the Whipple upgrade I'm just trying to weigh whether I want to be locked into only being able to use 89 octane gas in it all of the time or have the choice of 87 octane as well by keeping it the stock HO tune? Plus the Cam power band says it's from 1400 -5200, so I don't think that I will need to have the rev limiter bumped up to 5400 RPM.

I stand corrected. I know Larry used to sell cam/valvespring packages. The following link are upgraded valvesprings from Comp.

http://www.compperformancegroupstores.com/store/merchant.mvc?Screen=CTGY&Store_Code=CC&Category_Co de=BBVortecValves

My internals looked great at 500hrs so yours should look new! The stock GM lifters are a perfect fit. The Raylar HO 525/600's run these lifters. With the Whipple Stage 2 tune it requires 91 oct. I rarely run it though as my local marina pumps 89. With the 93 octane my transom soots up big time vs 89. IMO... You don't want to go above the stock rev limiter with stock pistons. No need to anyway with the 203 cam.

Did Larry tell you to bump your fuel pressure higher using the adjustable regulator? Whipple's tunes are based off stock 42-43psi KOEO.

https://www.offshoreonly.com/forums/velocity/351994-test-ran-new-raylar-goodies-2.html

I dont think you will need more than 42 PSI. Everybody gets all excited but once you run the whipple program I think he compensates and assumes 42PSI. Of course, you can get a O2 kit but my guess is that anything over 42.5 will be rich. The BP 203 is the Raylar version of the HO cam or only slightly hotter - Right?

Ahhh, the stock springs. I will bet you had a moment when you took them out. I know I did. I was like "This cant possibly be the springs that were inside my engine at 5000 RPM" they are equivalent to a Bic ball point pen spring - LOL.

LOL Yep the stock valvesprings are babies!! The 203 cam is 230/238 @ .50". HO is 222/232.

Hi thanks for the link to the valve springs, I tried it but the parts don't show up on the screen can you please provide me the part #'s that I would need. Do I just need the springs or are there are there other parts that I would need as well like different retainers / valve spring rotator eliminators? I have discussed this with Larry a couple of times and he says that most people run the stock valve springs with the BP 203 cam, he used to sell the valve springs with the kit but his valve spring supplier went out of business. I purchased the adjustable fuel pressure regulator directly from Larry as they use this on 2005 and newer 496 engines. He recommends just having whipple do the stock merc 496 HO computer program and setting the fuel pressure regulator at 50-51psi with the engine not running. Do you have the entire raylar stage 1 kit with head & Intake manifold? I'm only changing the cam, roller rockers, computer program to 496 mag to HO. Please email me as I want to make sure I'm getting the correct items as my computer is on the way to whipple!

Comp's webpage. Look up 8.1l and then valvesprings/retainers. It breaks down your options. They offer a conventional single spring and the more expensive beehive design. At minimum both will require retainers and shims to get correct installed height. Comp should be able to help with tech questions.

The 203 cam only has around .030" more lift than the 496 HO cam. I would upgrade to a stronger spring if it were mine. Especially if you plan on running WOT for any length of time.

The 50psi fuel spec is what Raylar advises for their complete HO525 kit. I would think with the 203 cam on an HO tune at 50 psi you'll be running crazy rich. Larry is the expert though and is probably erring on the conservative side.

I'm running Raylar's 80mm CoolGap intake and 1.7 roller rockers with Whipple's Stage 2 tune.

I have the 203 cam on the shelf. When my engine needs rebuilt it's getting Raylar's heads/cam and a forged bottom end.