I am in the process of building a 350 and have been looking at a lot of peoples engine combinations. I found out that a lot of people were using a head that was rated at 190-200 on the intake side. I found this odd because after calling world, AFR and trick flow, they all said that I would be best off with a head that flowed in the 180-190 range. Yes I did plenty of research, The combo I fed them for the engine was very similar to most 350s on the board, maybe even the same as a few. Supposedly AFR and Trick flow should support up to 500 hp. I am of course building a torque engine though. So, I was wondering why everyone went with their choice of cylinder head(intake rating wise)?

 

I assume you are actually talking about intake port size and not flow, correct?

I didn't go big, I went VORTEC!

It's not all about port size and it's not all about maximum flow. It's about power and efficiency and the Vortecs ROCK!

 

 

I've always read about how great the Vortec's were, but then I will see an article that will switch to a different head (Vortec to ___) and see more gains. Also The Fuel injected manifold choices are not as good.

 

Yes, sorry I didn't make it clear.

 

I think that this is one of the most common mistakes made on this (TPI) board. I fail to see how even an aftermarket tpi system can make efficient use of a 195cc intake runner. Even if your tpi does pick up a few extra ponies up top, your hurting the 'useable area under the curve' which is what wins you races. Just think about it, how long do you think your engine spends at peak hp during your average run down the strip. Not very long at all. Would it make sense to gain hp for that small amount of time if you actually loose hp during the majority of the run?

Expanding on this a little, a head with the same flow #'s but a smaller intake port volume will be a bettter head (with all else equal of course). This is because the port velocities will be higher with the smaller port which lead to a greater volumetric efficiency, amoung other things, which always leads to more power.

Other than possibly the LTx heads and surely the LSx heads, a vortec will outflow every other production sbc head made. These comparisons you're seeing are comparing them to aftermarket heads, which I don't think is fair due to the difference in price. Your not going to get a hp gain over a vortec head from a head that costs less, that's the bottom line.

I disagree. The only FI manifold that isn't capable of working with the vortec heads is the Holly Stealth Ram. As far as I am concerned, the vortec/fastburn exclusive ramjet manifold more than makes up for that loss.

 

Everything is great ... and everything rocks ... until you actually have Dyno Numbers and 1/4 mile times to prove it. In sooooooooooo many cases it doesn't rock as much as you thought. Everybody says "this is good", "that is good", etc. but very few actually put up the proof to show it is really good. Stock iron Vortec heads aren't 'great'. They are ok - but definitely not great. Just depends on how far you want to go and how much money you have to spend. Don't get me wrong - those heads can be made to flow very nicely. But, out of the box, they are nothing compared to a set of AFR's. Run the AFR180 heads with the TPI and your car will scream.

Tim

 

A well-flowing ~200cc runner head on a 350 isnt necessarily a bad thing. Pairing them with TPI and a short cam is, however. It all depends on the combination of parts, and where you want the power in the rpm range.

 

The same could be said concerning price...

Regardless Tibo, if your building for torque, I wouldn't suggest anything near 200cc for a 350. Thats given. The question is how much do have to spend on a set of heads?

 

I have the ability tospend up to $1,299.99 for an aluminum or I would'nt want to spend more then 800 for a cast iron. AFR actually recomended the AFR 180's for me, just as Traxion had said. I am using the HSR for fuel injection with my Mega Squirt ECM. I am not looking to turn the engine past 6,000 RPM as it will be a daily driver with some track and road course. So I will have to finish the cylinder head decision and move into the cam decision. Choices.

 

If you have that much to spend, why not get the AFR 190's? I'm sure somtime down the road you will be able to put the other 10cc's to use, whether it be with a 383 or a bigger cam.

 

I understand that the AFR are really good heads but what about the Bordix heads ported out. I have seen some really good flow numbers out of the Brodix heads, even better than that ported AFR with a lower price



I know that these are larger than what he is looking for but these are actually on my friends 383.

 

You did not say what the use of your car will be such as a street/daily driver. I agree with what has been said in that the AFR 180's will flow enough to most likely make all the HP you want. The trick is to make the heads the most restrictive part of the whole intake and exhaust system.

Kevin91Z is making right around 400 flywheel horsepower with 170cc heads and LTR TPI. He has since modified his car some and I will be anxious to see what the results are.

I bought some Brodix Street heads in 1990 for my GTA and that is what I'am using. They have 170cc runners. If I were buying today I would go for either the Brodix heads or the AFR 180's. At the moment my car is at Dyno Don's getting 10.5:1 compression, the exhaust system squared away, a ZZ4 cam, port matching and a new custom EPROM. I'am looking for around 300RWHP. By the way I'am going to have the Edelbrock TPI manifold and SLP runners Extrude Honed. I want the heads to be the bottle neck. Allen

 

I went ahead and bought a pair of Trick Flow Kenny Duttweiler series. 64cc 195 intake volume. I decided to stay aluminum because I would be able to run a lower octane gas. I am looking at a 9.3-9.6 compression ratio, so 89 octane should do me fine. I actually did not look at the brodix, I was thinking they were iron. The AFRs were what I wanted, but the wait on them and the price was what got me. They also would not accept my older style 1.6 ratio roller rockers.

I decided since it would mainly be a street car with very limited strip/roadcourse time, I could just save some extra money and spend it on the rear end.

The heads have come in and look great. They will be with a hot cam and HSR. I thought about the canfields, but there was a wait on them also.

I decided to go with a little higher reving engine. I read the article in "Camaro performers" of a TPI car with the hot cam and Trick Flows was dynoed and stripped and then changed to a HSR. The car ended up getting close to 1 second better in the 1/8 mile, even though it had less low end torque. So I decided to go close to that same route. They dynoed it at 342 hp. I will have a leg up on them in parts, so I am hoping for 350-400 hp.

Wish me luck and thanks for the guidance.