Ported LD4B :(

[ValerianMagnum]

Bought a rare LD4B for my 318 ( 1971 casting ) and a bunch of other parts / engine gaskets / copy of an edelbrock air gap / 650 dp carb / 5.9 magnum exhaust manifolds/ dual exhaust set up .............* My big Question is unfortunately the LD4B is massively ported to the 340/360 gaskets , i didnt know and the ex owner didnt know either, it was to put on my standard 318 heads, i wanted to do some test with the ldb4 and my carter 2bbl and my 650 holley dp , cam swap will be later , * How hard is it , To port 318 heads to a 340/360 gasket , never did such a thing , thanks guys

 

[moparmandan]

@318willrun has some great videos on here about porting 318 heads. Been awhile since I watched them, I don't think he hogs the intake out to 340 size, but the videos are very informative. Will give you some good ideas and a direction. Or maybe you may just want to pop for a untouched ld4b.
Throwing sod is hard work. Roofing is hard work. Porting heads is not hard, but it is time consuming.

 

[MOPAROFFICIAL]

Can be done. Still needs to descend after the window... so that you don't blow through the roof.

 

[junkyardhero]

i'd suggest you just gasket match it and not "full on port" them. get some color on the head surface, use a gasket as a template and scribe a line. i don't know what you skill level is or how much experience you have with a die grinder or porting, but if you're relatively new to this type of thing you can start out with some sanding rolls like these

you're not removing a tremendous amount of material, and these are very forgiving if you get a little Shakes McGee with the tool.

 

[toolmanmike]

Bought a rare Ldb4 for my 318 ( 1971 casting ) and a bunch of other parts / engine gaskets / copy of an edelbrock air gap / 650 dp carb / 5.9 magnum exhaust manifolds/ dual exhaust set up .............* My big Question is unfortunately the Ldb4 is massively ported to the 340/360 gaskets , i didnt know and the ex owner didnt know either, it was to put on my standard 318 heads, i wanted to do some test with the ldb4 and my carter 2bbl and my 650 holley dp , cam swap will be later , * How hard is it , To port 318 heads to a 340/360 gasket , never did such a thing , thanks guys

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LD4B ? THe previous owner should have bought a LD340 instead of hogging out a LD4B.

 

[Mattax]

How far up the runner did they grind? First 1" or so? Weld up the LD4B ports and then match that to the gasket. Also take the opportunity to line up the centerlines of the heads to the centerline of the intake ports.

Is that divider cut down as well? That might help on the larger engine at high rpm. Effect on your engine, hard to know.

Keep in mind the old Hot Rod test of a 340 where the LDB4 appears to hurt WOT performance below 3000 rpm.
"Appears" is key here. I don't know enough about the engine dyno and test method to know if torque and hp under 3500 rpm are truly comparible.
Edelbrock LD4B

 

[ValerianMagnum]

No the devider is still there , i was dissapointed because i bought this intake for my stock 318 , wasnt expecting big ports like that, i want to do a test and try an aluminium intake with a carter 2bbl bbd and dual exhausts , this fury will be a driver , not a race car

 

[Killer6]

No the devider is still there , i was dissapointed because i bought this intake for my stock 318 , wasnt expecting big ports like that, i want to do a test and try an aluminium intake with a carter 2bbl bbd and dual exhausts , this fury will be a driver , not a race car

You didn't include pics of the ports vs gaskets, every stock LD4B had larger-than-stock 318 ports, but not quite as big as 340/360 ports. It's no problem to match them ~3/4" into the port, & it'll run fine, so are You sure they are all the way to 340 port or????

 

[ValerianMagnum]

My comparaison to my edelbrock air gap , same size

 

[junkyardhero]

doesn't look that bad, just get it matched up and knock a little like 3/8" bevel into the heads just so there's no step and call it done.

 

[Killer6]

Yeah, that's hogged pretty good, they may have run 340 heads on a 'teener & wanted the velocity of the slightly smaller runners, but the floors are pretty low on the bottom plane...wrong tactic there.

 

[ValerianMagnum]

Im getting a refund, bought used 650dp holley and a new chinese carter 2bbl copy , still in search of a small port intake for my 318