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There is only a couple kits for big block Corvettes and they are really pricey.
If I remember they were complete kits and you needed to purchase all new accessories with the kits.
I decided to stay with the V belt system.
No issues with the March Performance system. Been working great on my 496 for 10 years. I did swap to the larger crank pulley to speed up the water pump. No clearance issues. Added an extra idle pulley as well to help with belt wrap since I don't have A/C and a regular rotation water pump.
I bet a stock system from a big block truck would work. I have one from a small block on my car, fit under the stock hood. Cheap enough that you aren't out much if it doesn't fit.
I too have the March Serpentine conversion system on my 1968 427. I don't have air conditioning but the parts were readily available. The system has a good appearance and the pulleys are nicely made from billet aluminum. I bought mine decades ago and really appreciate the look and simplicity of having just one belt.
The only negative about my March System is that some of the brackets had Shiny Aluminum Powder coating on them. After a year or two I had sheets of powder coating coming off the flat surfaces. Somebody didn't prep the metal surfaces prior to powder coating and that is likely why it has come off. Fortunately I can powder coat here in my shop.
The pulleys all came with small caps made for them and the system looks good on the engine when the hood is open. I have been satisfied with the quality of the components and it has weathered well. Take look at March's website and check out the options they offer. The are not cheap but for that matter they don't look cheap either.
No issues with the March Performance system. Been working great on my 496 for 10 years. I did swap to the larger crank pulley to speed up the water pump. No clearance issues. Added an extra idle pulley as well to help with belt wrap since I don't have A/C and a regular rotation water pump.
@SteveG75 This is very helpful information, as are the photos! You mention that you added an idler... are there provisions in the provided brackets for this via March Performance, or did you fabricate/machine your own? I can't determine via the photos. Was this a piece-of-mind measure, or were you experiencing noticeable slippage?
I'm about to pull the trigger on a 454 Mark IV big block build and swap in my '74, and the20585 kit is what you'd identified as a perfect fit. I'd prefer to do this right the first time . Thanks in advance.
EDIT: 20585 is NOT the correct part number!
Last edited by Aeredan; Aug 7, 2023 at 09:39 AM.
Reason: Incorrect Part Number!
The March system is a nice kit, they do make it for AC and they also offer a black finish. I believe CVF also makes a kit as I looked at several, been very happy with this setup. They do offer an additional idler if you need more belt wrap. They give you the part number and placement in the kit.
The March system is a nice kit, they do make it for AC and they also offer a black finish. I believe CVF also makes a kit as I looked at several, been very happy with this setup. They do offer an additional idler if you need more belt wrap. They give you the part number and placement in the kit.
@Amelio Many, many thanks for this! That's a spectacular looking setup you have... thank you for taking the time and effort to post the info and pics! My wallet is soon to be much lighter.
@SteveG75 This is very helpful information, as are the photos! You mention that you added an idler... are there provisions in the provided brackets for this via March Performance, or did you fabricate/machine your own? I can't determine via the photos. Was this a piece-of-mind measure, or were you experiencing noticeable slippage?
I'm about to pull the trigger on a 454 Mark IV big block build and swap in my '74, and the 20585 kit is what you'd identified as a perfect fit. I'd prefer to do this right the first time . Thanks in advance.
Mostly peace of mind. Used to get a little belt squat when cold. No more.
OK, here is the info. The idler I added is in the top water pump bolt on the driver's side. Longer bolt and a spacer plus idler is all that is required. You can just see the idler under my radiator hose in the pics.
Last bit of info. I only use Gates belts from NAPA. Zero issues. Here is the belt I use now with the larger crank pulley, power master alternator pulley and idler.
Mostly peace of mind. Used to get a little belt squat when cold. No more.
OK, here is the info. The idler I added is in the top water pump bolt on the driver's side. Longer bolt and a spacer plus ideal is all that is required. You can just see the idler under my radiator hose in the pics.
Last bit of info. I only use Gates belts from NAPA. Zero issues. Here is the belt I use now with the larger crank pulley, power master alternator pulley and idler.
Outstanding! I cannot thank you (et al) for your thorough responses and taking the time to further provide pictures and information. I pulled the trigger on the purchase - wish me luck!
EDIT: Do NOT purchase the 20585 kit as while it's for Big Block Chevys, it is not for Corvettes (the power steering pump brackets will not work - a compact pump+remote reservoirs is required). I contacted both Summit and March Performance and returned the power steering brackets and pulley, and ordered replacement parts:
20177 Power Steering Bracket
P315 Power Steering Pump
619 Power Steering Pulley (press-fit)
The other pulleys (crank, short water pump, alternator) and brackets from the 20585 kit will work, thankfully. Again, do NOT order the 20585 kit for the C3 Corvette... call March Performance (or a competitor) directly for the precise part numbers.
Last edited by Aeredan; Aug 7, 2023 at 09:38 AM.
Reason: Incorrect part number
. Thanks in advance.
