What compression ratio are you looking for? If you have not bought your roatating assembly yet that is one thing you need to consider that nobody has brought up yet. On a 383 with a flat top you are looking at 10.5:1 with a 70cc chamber. In most cases we recommend at least a 195cc head on a 383 but each combination is different. You can get into the 175cc head if that is something you desire but you will have a large dish piston to keep it on pump gas. Keep in mind when you are comparing heads, look at the components that are used in them..ie..springs, retainers and the valves. If you have any further questions I will be happy to help you. Please contact me at 330-630-1555.

Gregg
Trick Flow tech

 

Looks like you were right Will. With the 175cc debunked (for a 383) by TFS themselves, I'll defer to your original analysis on the topic.

Try to throw a company a bone!

 

Don't these 175 TFS heads flow in the 215 cfm range at .400 lift, and 180cfm range at .300 lift?

I believe the AFR 180 street ports which arent much more money flow in the 240 cfm range at .400, and 200 cfm range at .300 lift.

20-25 cfm difference in low lift numbers which even a stock TPI can use is huge imo!

Am I missing something here? Maybe I am....

It's really a no brainer. And to boot I know where you can get a great deal on a new set.

It's not about max flow numbers, it's about the flow numbers from idle to redline.

 

I totally agree. Price was the only issue detering a straight AFR recommendation. If the OP can get hooked up with a great deal on 180's -- especially for a long-tube 383 TPI application, it's a much better option. Probably even better than the competition's 195's. I'm 99% sure I could have installed AFR 180's (vs. my 195's) and lost zero power.

 

TFS 175's are targeted for small bore applications with smaller 1.94" valves and 56cc chambers meaning you can throw these on 283's, 305's, 327's and mild 350's. I wouldnt use them for anything larger even a short rpm range 383. Hotter 350-355 motor I wouldnt use them.
AFR 180's have larger valve and wouldnt work well on small bore 305 type motors. They are targeted for 4" bores.

Most 195cc heads have a cross section around 1.9-2.0" square which is a good size for most 350-383's operating to 6000-6200 rpm. For more rpm, 200+cc with 2.0+ sq. inch CSA's. For less rpm, just run smaller cam. I dont see a fit for a 180cc AFR head when the 195 will do everything the same even on mild 350's. Thats probably why 90% of the builds you see use the 195's for 350's to 400's.

383 needs a good bit of airflow with that longer stroke. EVEN in a TPI application where the induction system may only flow 240cfm, the larger head makes sense. The intake can be a restriction to the head, there certainly is a flow loss most of the time. But there have been cases where improved head flow when used on same intake has produced more power. Any by improved head flow I dont just mean flow numbers but flow quality. Theres more to it than flow numbers, the velocity profile is one and cross sectional areas another. They go together in making a good port. AFR's are known to be fast. Too fast is not always a good thing. Usually becomes a problem when a port CSA is too small for the rpm range for the given cubes of the motor. For the most part however, AFR makes a great head for the sub 6500 rpm ranges found on street motors.

 

Don't disagree with anything you posted. But, I would be very interested to see where improved heads really helped with a TPI application because I haven't seen it. For example, I mean something like a change from well-ported 113's, TFS 175's, or TPIS cnc-ported to something like an AFR.

I haven't noticed one that fit your bill during the 3-4yrs I've been in the Tech forum. OTOH, I've definitely been surprised at some of the "lesser" heads power levels in a performance TPI build. As an example, I posted a link in this thread showing AFR 195's as they stacked up to a comparable TPIS cnc-ported 113 build. I didn't see significant difference.

FWIW, I do see the 195's at the best choice for anyone contemplating a better-breathing intake as an option for their 383 TPI.

 

I think its about matching the combination of parts. That link you posted were 2 different cars with 2 different transmissions and neither were cammed right IMO.
Both cars were in the 320whp range.... I've seen 320whp made on stock 113 heads with hotcam and TPI on other dynos thru automatics...I dont think either of those combinations were to their best potential for whatever reason...possibly the cam but just didnt seem to come together like they should. They should have easily been a 340-350whp setup but TPI is limiting the true potential.

Few guys over TGO have made around 340-350whp with basic TPI upgrades and AFR's. I dont recall the exact numbers but I know one guy had improved power with his AFR's over some ported edelbrock Etec 200's or it may have been some old dart 200 castings...

I do agree the differences wont be stellar as long as the cam is right for each type of head. But depending on the port speeds and size, they may take different cams. AFR's do have fast velocities on the bench and thats why they flow more than most heads. This can be good in the right situations, and low rpm useage, to me, would be best suited with a faster velocity port.

I'd like to see a back to back test each using the proper cam for the rpm range and head flow characteristics.

A good look at making big power in the 2500-6500 range is the Engine Masters Challenge. They maximize power from 2500 to 6500 and even tho thats 2000 rpm higher than most TPI motors, same concepts can be applied to the motor for that 2500-4500 rpm range because power everywhere is important. You need to have good flow thru a large valve and have very fast valve motion from very aggressive cams. Wont last as long on the street but makes big power. Thats the general trend in EMC, and has been relatively successful on street motors.

 

The right cam is definitely important. IMO a TPI cam would have less duration than a hotcam/TPIS cam possibly in a single-pattern or (really) reverse-pattern profile with steeper ramps. OTOH, I can't say I've seen a TPIS (or AS&M) tubed application that made 340whp with any head. I thought it took the mega-ported stuff to make some impressive numbers.

Kinda seems like 320ish is the limit for the factory-cast large-tube stuff. I suspect the TGO guys build more TPI stuff?

I think the biggest point you made to support my view is how 113 heads can make so close to the aftermarket-headed stuff ON A TPI. Yes, the intake is the limiter...which is also my point. AFR's flow a ton more but can't make much more power under a TPI.

Since the OP is looking for a budget head option, that's why I suggested somthing that flows more than 113's. And, enough so that they had a decent chance of getting to that 320ish number. Or even to 340ish with a 383, a stick, and a perfect setup.

Port speed was another consideration which is why I suggested the 175's. They're still bigger than stock and flow a greater percentage in relation to the port-size increase.

I can't remember if I suggested TPIS-ported 113's ($1100ish). From what I've heard, they end up in the 185cc range, are CNC-ported, and hit some decent numbers (in the link). Add a 383 shortblock onto that (Matt's) dyno and you're at those numbers you've seen at TGO. Hard to imagine AFR's stuff going even 10whp more than that. Enter the budget issue.

 

You can get AFR's for 1300 or so these days from the right people. They arent much more than other heads, so I consider all the heads in the 1100-1400 dollar range about the same, meaning whats a few hundred more if you are spending 1100 already?

There are some other budget heads like Darts SHP castings but the ports really respond to porting to correct the casting flaws. They make ok power out the box but never compete with the newer Dart pro 1's or the like.

Jeg's brand heads are basically pro-filer castings which are great castings to start with. Also leave room for alot of work and improvement if you want to upgrade down the road.

+10-15 hp is what I'm thinking the AFR's will make over most basic as cast heads due to improved runner shape and flow velocity. More hp difference as rpms increase but with the shorter powerband, smaller differences. This still can be noticeable improvement at the track however. 20lb-ft and 12-15whp on my old car picked up 2 tenths and 2 mph at the track. That was just in improving the dyno tune. A head that picked up power like that would show similar results

 

bite the bullet and spend the money for either trickflow or AFR's. I purchased AFR's from Jim Barth and have been very happy with the performance and the service I received from the pro's at AFR. They spent a lot of time with me and were right on the money with their answers.