Thread: port size

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right now i'm building a street/strip 355 for a camaro. I found nice set of brodix aluminum heads for about $1,000, but have a hard time picking the right port size. the heads are either the IK180's or the IK200's. the engine will be driven on the street 80% of the time heres the flow numbers
IK180 IK200
Intake exhaust intake exhaust
.200 138 112 .200 123 100
.300 188 149 .300 181 145
.400 234 167 .400 230 164
.500 243 175 .500 253 171
.600 245 178 .600 261 176
the cam is 230 dur. with a .500 lift
i much rather go with a smaller port, but the added flow could add quite a bit of top end power, also i hear of lot of stories guys putting smaller port heads (170-180cc) on their 355's and 383's and then bumping up to the larger port 190-210 and not lose any low end torque ,but gained a lot of top end horsepower. any suggestions would be awesome.

Originally Posted by vortec king

right now i'm building a street/strip 355 for a camaro. I found nice set of brodix aluminum heads for about $1,000, but have a hard time picking the right port size. the heads are either the IK180's or the IK200's. the engine will be driven on the street 80% of the time heres the flow numbers
IK180 IK200
Intake exhaust intake exhaust
.200 138 112 .200 123 100
.300 188 149 .300 181 145
.400 234 167 .400 230 164
.500 243 175 .500 253 171
.600 245 178 .600 261 176
the cam is 230 dur. with a .500 lift
i much rather go with a smaller port, but the added flow could add quite a bit of top end power, also i hear of lot of stories guys putting smaller port heads (170-180cc) on their 355's and 383's and then bumping up to the larger port 190-210 and not lose any low end torque ,but gained a lot of top end horsepower. any suggestions would be awesome.

How many rpm's will the engine see?

6500rpm absolute max

Originally Posted by vortec king

6500rpm absolute max

I would run the 180's.
Do a bowl blend,gasket match and call it good.

I built a 383 and bought the 180cc heads. I run about 80% of the time on the street also. For the street I also used a 650cfm carb and the low end punch is great. With your 355, running the 200cc heads on the street is a little overkill. Your engine will run better and youll have better throttle response with the 180`s.

I agree with both the above replies. Cubic inches times 1/2 is a good rule of thumb for a street motor. 355 times 1/2 = 177.5 cc intake runner volume.