better oem intake ?

#1
Question: Of these 3 intakes which is considered the best stock intake for a 348 with small port heads with the matching oem carb for the intake? The aluminum 3780540, the aluminum 3797776 360 hp 409 or the cast iron 340 hp 409 3830831 . Visually the 340 hp and the 360 hp manifolds look similar but different metal and different carbs. Just curious.
 

Don Jacks

Well Seasoned Member
Supporting Member 3
#2
The 540 most likely,but more expensive when found than a new Edelbrock Performer[which is the best manifold of them all].The ultra rare 776 would be even more expensive.For your cam and the rest of that set up in that engine,that 831 will be tough to beat.All of those intakes will fit a modern carb without adapters.
 
#4
The ultra rare 776 intake is on eBay now for $825 . It's been a while since I've seen the 540 for sale. Folks are proud of them both for sure. I'm just being hard headed. I know I should get the avs2 and the eddy intake. I've got a solid built 348 short block stock stroke with ross pistons , eagle rods and balanced. Butttttt I got the 58 791 non spark cooling heads . I did clean up the bowls and ports . Cam lift .481 212 / 212 @ .050 262 adv duration aprox. 1200 - 5300 rpm 110 ls. I already have the 63 Rochester 409 340 hp carb and the 831 intake. Trying to determine if the extra expense would be worth it.
 
#6
Ouch more money. My block doesn't have the extra casting for the water port to the spark plug cooling port on head. Can you plug the water port on the 817- 833 heads so they don't leak? Looks like I'm limited as well with the cam. I think my feet is cemented with what I have. I don't know if the eddy and the avs2 will give much more than what I already have. Thoughts?

PS. I found this site after I was in the build to far . I should have got a latter block and heads and stroked it. :doh
 

Don Jacks

Well Seasoned Member
Supporting Member 3
#7
Yes,the heads CAN be plugged.I'd suggest drilling,tapping for small pipe plugs.While the eddy intake will help,it won't be much with the tiny cam that you have,the carb will make a great deal in a positive way..Another limiting factor may be exhaust,,depending on what you end up doing.
 
#8
Ok, would it be feasible to do the avs carb on the 340 hp cast 409 manifold. Will it fit? 2.5 exhaust manifolds for exhaust. I'm stuck with the heads and cam:doh
 

Don Jacks

Well Seasoned Member
Supporting Member 3
#9
Yes,the avs will bolt right onto a 340 horse intake.It's always a good idea to put a heat rejection spacer between the carb and manifold,especially with todays fuel.
 

scott hall

Well Known Member
Supporting Member 1
#10
How early is the block. I’ve got a feb 58 block and it has the bosses for the cooling holes they just weren’t drilled. Might be your case also.
 
#11
My block is an L30 57 3751872 250 hp power glide block , it doesn't have the added casting material to seal the gasket.

So would the move to the avs2 make since or the big 4gc that I have? Goal was for a good sounding engine with maybe 300 hp. Dual exhaust with glass pack , auto trans , no overdrive. Something that would spin the wheels when I felt like it and take me back 50 years! It will be in a 56 chevy. I coulda shoulda donna. Trying to fix my poor choices and make the best of what I have. :dunno2
 

Greg Reimer

Well Known Member
#12
That block is possibly a replacement block, designed to replace the '58 non-water cooled spark plugs, or it would be correct for th 59-61 348 as well. If you put the later head on it, water wouldn't circulate around the plugs,but it probably doesn't have to. You could drill the holes for ir,use a head gasket for a template. Make sure you know what spark plug your heads need-the '58 non water cooled heads use a short plug like a 283-327, the water cooled heads use a long plug like a 409 uses. Don't ever put the long plug in the '58 head, they will go in so deep that the piston will hit them,breaking and bending them,and you will have to pull the heads to get the plugs out and retrieve all the debris and metal particles in the cylinders. Not a good time.
 
#13
Engine is assembled , not installed, the changes I could make now would be intake and carb. I'm leaning toward just the carb as I think I could tune it easier with the kit. I'm thinking the big 409 4gc if it needed to be tuned for the smaller displacement might be a challenge. I could wait and see how it runs I guess.
 
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