clear things up here..on a SB 2v-318 it has the small ports & never used a 4-v intake on them. 273 had a open plenum low rise 4 hole intake with the small ports. this is what fits the 318 best as a stock OEM intake.

a factory 4-v 318 came with the 1.88/1.60 valve 360 heads large port heads. IMHO.. a 2.02/1.60 X head on a 318 cyl bore shrouds the valve.

a edelbrock 318/340/360 performer is a stock OEM cast iron replacement and has the spredbore flange as well as a square flange ** use of a edelbrock flat adaptor plate is the best fit over the thicker spacer adaptors IMHO.

in the instruction sheet it clearly says it has the large 340/360 runnners BUT NECKS DOWN to a 318 port size. also states that if used on a 340/360 head to gasket match the first 1" into the runner this makes the intake a large port 340/360 intake ONLY after gasket matching

so when looking for a used one check the runner for porting.

LD4B is a 318 small port reverse copy of a large port LD340 the LD4B is one of the best duel plane small port intakes for a 273/318 small port head.

LD340 is a high rise duel plane intake with large port/runners and does not give up very much compared to a edelbrock RPM & RPM air-gap intakes

edlebrock RPM & air-gap RPM are the best newer intakes but only slightly better than the 40-50 yr old LD series of intakes

Holley STREET dominator is a low rise, single plane, spredbore intake with small port/runners for a 273/318 head works very well on a street engine to be a single plane intake. I like mine as a daily driver.

Holley STRIP dominator has the 340/360 port/runner size and is another low rise single plane intake that works well for the strip. this is what I remember 340 engines getting back in the day.

no need to talk about the small port sp2p gas miser intakes they are not for HP performance


I have a
LD4B on a 318 #302 heads
Holley STREET dominator on a 318 #302 heads
RPM air-gap 318 360 heads

all have the hughes whiplash roller cam and run rather well as daily drivers in my mid 80s trucks

IMHO cant go wrong with any of these intakes.