I have a new 502 gen 6 longblock and noticed that the merlin intake that i bought only has 6 holes on each side to bolt down, where the stock gm heads have 8. The two bolt at top of each intake runner cant be run on aftermarket intakes from what i see, because there are no holes in manifold. So what do people do, do i need to plug up head holes? Do they go into the head intake runners? Or just leave them out.


Second the 502 block has provisions for a fuel pump on block casting....I thugh this was weird, cuz my gen 6 454 didnt have provisions for a pump, I'm running an electric one but it weird to e that the 502 gen 6 has a block off plate on it??

Nobody knows what to do with the extra holes in heads.......everyone must be running into this??

i ran a merlin inteke on a set of factory gen 6 heads, I didnt do anything with the extra holes. I just put the intake on and all was fine.
I have a gen 6 502 block, and it does not have boss for fuel pump, but maybe some do.

What did you run for gaskets, did they seal on the brass part on the cooling passageways, i was told some gaskets are to large and seal on the aluminum defeating the purpose of having brass lined for salt water.

The extra holes are what's known as 'blind' not open to coolant or oil so they are fine as is.

Some Gen VI motors had provision for a Mech Fuel Pump, no big deal. But remember, some after market Gen VI cams have no mech F/P lobe! Just block it off and stick with the fuel system you've already got IMO (unless you have a holley elec pump??? In which case relace it!)

I have a Brand New Holley Red marine pump.....I was told that the pump will work fine for my application...

Ghostrider do know if i need to replace the gear on my distributor?? My distributor cam from a 1998 454 gen 6 L29 330hp carb motor??

Most roller cams have a press on iron gear and do not require a specific distributor gear, you just need to check the cam specs to be sure. as for intake gasket I used the felpro 1275 gasket, they also make the same gasket with red rubber seal built in. Many poeple on here have had roblems with the holley electric fuel pumps, me included. If my motor had a boss for a mechanical pump I would go that route for simplicity.

Spot on. Stock cams in Gen VI motors can take a standard dist gear, most modern aftermarket roller cams will now too. You should be fine. Same gasket set I used too!

I wouldn't trust that Holley pump if I were you. I had a Holley blue that didn't last through testing! Correct me if I'm wrong but as far as flow / pressure goes for Holley it's Red then Blue then Black right? I doubt that Red would flow enough for a 5.7 in a marine app, let alone anything bigger!

a lot of the race type intakes eliminate those top 4 bolts, no issues there, they made a line of 502 crate car engines that had fuel pump mounting, if you are already plumbed for the electric use it....Rob

I have a Holley red Pump on the 468 in the Baja 24 Sport I bought last fall, it has Gill Exhuast, 750 Holley with stock jetting, think they are 72 at all four corners, Weiand Intake. I only got to run it one time before I had to put it away for the winter. I was thinking on going to the Blue Pump and a 850 Holley, sounds like I need to least step up on the fuel pump.