To Port or Not to Port

[Dano 1]

I'm picking up a set of 452 head castings that the current owner had tuned up with a cleanup decking, 2.15/1.81 intake/exhaust valves with a 3-angle job, new guides etc. but no port work. My current 346 heads are pretty tired (pitted seats, loose guides etc.) so when these popped up for cheap I snagged them.

My question is, is it worth porting these to make better use of the bigger valves or will I not see enough gains on the street to justify the time or cost. I've never ported before but I'd consider doing a basic job myself. I imagine to have a shop do even a basic 'cleanup' or pocket port and gasket match would be pretty expensive even if the rest of the work has been done.

Current engine combo is a very mild 1971 440:

Stock pistons, rods, crank etc.
Melling MTD2 'rv' cam
Exhaust duration @0.050: 214
Exhaust lift: .443in
Intake duration @0.050: 204
Intake lift: .421in
Edelbrock CH4B intake
Holley 750 vacuum secondary
1-3/4" primary headers

The main reason I picked up these heads is because they were just 'gone through' and are cheap. The bigger valves are just gravy assuming I don't actually lose performance due to a drop in velocity. Thoughts? Thanks!

 

[440Coronet500]

Bowl work, just cleaning them up will help. Watch David Vizard's videos, enlightening to say the least. 440'

 

[4speed68rt]

It sounds like you aren't looking to burn up the dragstrip, and you dont want to spend alot of extra money, so I say to just run them as they are.

 

[SS350]

I think you probably need these...
1 Stage V Racing Components

or some indy heads - since 500 ft-lbs might not be enough for the street.

just sell that bumpside ;-)

now in all seriousness you know my vote!

 

[33 IMP]

I doubt that you would feel anything from porting on a mild motor like yours. You will feel an improvement with fresh heads.
Runable, fresh, and cheap? Win, win, win! Run em.

 

[INTMD8]

If you have the time, why not.

Even bowl blended the heads on my 59 Cadillac (and reground cam slightly bigger) Runs great

 

[R413]

Cam to small for valve size. I’d get different heads for your engine. It’s all about the combination working well together, and these big valves are bad news to that, porting worse.

 

[Dano 1]

I doubt that you would feel anything from porting on a mild motor like yours. You will feel an improvement with fresh heads.
Runable, fresh, and cheap? Win, win, win! Run em.

That's kind of where my head is going 33 IMP, I'm not racing but also don't want to leave low hanging fruit power gains on the table. I don't have enough butt dyno experience to know how different things will effect the feel etc.

Cam to small for valve size. I’d get different heads for your engine. It’s all about the combination working well together, and these big valves are bad news to that, porting worse.

Can you elaborate on that R413? I was a little worried about a loss of velocity with the small cam and larger valves, is that what you're getting at? I'm still learning so I'm all ears to more experienced voices.

 

[Curiousyellow71]

We have spent considerable time porting and checking cfm with a flow bench. There is truth as far as velocity being lost with a huge port but I don't think that is the case from what has been described here. 452s are one of the easiest heads to port and gain. You will have modest gains porting with a 204/214 cam (we had that cam in a 440 with ported heads), but porting will make more power. Mopar steel isn't much fun to grind...but no reason not to port if your up for it. At least port the bowl.

 

[Geoff 2]

The cam has less duration than the factory Magnum cam, so enlarging the ports will do nothing.
I would have a valve job done, remove any sharp edges in the ports.

 

[Outlawd]

While you got the heads off I would slip in a 509 purple shaft and toss on some eddy alumi heads and your set for great street performance and awesome sound at idle. jmo

 

[INTMD8]

^ Agreed it could use more cam.

Disagree that properly ported heads would do nothing without more cam.

 

[33 IMP]

I don't think anybody said it would do nothing (could be wrong, havent read all the posts.). I just don't think it would appear at the seat of the pants.

 

[Phantomx]

I think I’d look at doing a 30 deg back cut on the intake valves if they aren’t done already. That is supposed to help flow quite a bit in the .100-.400 lift area. Also maybe radius the bottom edge of the exhaust valve too. Both cheap mods that should help a mild combo. I plan to do these to the next engine I tear into.
Travis..

 

[Runcharger]

Make sure the seats are blended into the bowls. With a fresh valve job though make darn sure you don't knick a seat etc. Be really careful.

 

[oldkimmer]

Hopefully they opened up the area under the seat when they put in the bigger valves. If not , it needs to be done as described in post 15. Kim

 

[Dano 1]

Thanks for all the feedback everyone.

Hopefully they opened up the area under the seat when they put in the bigger valves. If not , it needs to be done as described in post 15. Kim

It looks like they did a bowl cut on the exhaust side but not on the intake side. There's some sizable ridges around the valve seat that will have to be dealt with.

I think I've settled on gasket matching and port cleanup, it's fairly obvious where the trouble areas are now with the larger valve openings so I think touching those areas up and a gasket match will be a good balance of time investment with payback given my mild combo.

I'll let everyone know how it goes when the chips settle.