GS4-LT1

Just wanted to post my experience with the Trick Flow 21* heads I put on my 94 this summer.
Performance wise I was very dissapointed. My Vette ran a best time of 12.4 @ 112 mph before the install with the stock heads. I have cam, headers, gears, converter, etc. Motor is stock bottom and cubes. After install ran a best of 12.2 @ 112. Nothing else changed, 60', 1/8 mile times all the same. I even had the PCM retuned for the new heads through PCM4Less.
Installation was a pain as well. The dowel guide holes had to be drilled out because they did not match the dowels on the engine. The push rods rubbed up against the heads even with the longer pushrods Trick Flow recomended. The casting flash in the ports was unbelievable. For the money and results I have seen else where, I should have taken my stock heads and had them done by LE or AI. I say (JMO) if you are thinking of getting these heads do not waste your money. If you did buy these heads and had a favorable experience please post and let us know. Thanks!
-Mike

STL94LT1

I was wondering when someone would try these heads. That's good to know.

GS4-LT1

Yes, I was expecting/hoping for 11.9's at around 115mph.

96GS#007

I'm not a drag racer, but I thought the rule of thumb for street cars was that it took 10hp for every tenth of improvement? If so, picking up 20hp with just a set of heads isn't bad IMO.

It is disappointing that the install was not straight forward.

GS4-LT1

Weather was similar, track was the same. Cam is the ZZ409 from TPIS, Converter is a 3000 stall from Kane(brake stalls at 1900), gears are 3.54. Funny thing is I forgot to mention I used the thinner head gaskets (.029) with the heads and I have heard of guys picking up a solid tenth just from that. My MPH is what is so dissapointing. Bigger ports and valves=more airflow, more airflow=more horsepower...Right?

1989TransAm

"Bigger ports and valves=more airflow, more airflow=more horsepower...Right?"

It all about the proper airspeed.

96 lt-4

Velocity makes a huge difference.
Have you had it on a chassis dyno or wideband to make sure your tune is where it needs to be?You may not have it optimized.
What are the runner cc's on the trick flow?

Joe B.

Same heads as in this VETTE mag test? Their cam is similar to the Hotcam.
http://www.vetteweb.com/tech/vemp_10...e/viewall.html
Some info from Popular Hotrodding
http://blogs.popularhotrodding.com/6...ads/index.html
Lots of casting flash, how did the CNC work look?

cv67

Was yours mail order tune or real time?

185c

100 51 58
.200 136 98
.300 191 136
.400 230 163
.500 253 177
.600 254 190



If 60'and 1/8 are the same then the .2 drop is in the last 1/8
mph shouuuuld go up some; def making more power
2-3 tenths drop for a head swap isnt horrible.
Id guess the mph should be improved, hmm.

B.Cunninhams stok LT1 heads for reference.
The intake had been touched very slightly imo probably few cfm more than stock at the time. (we quit before really going farther and bought afrs)
Intake typically about 200cfm stock,. iron heads supposedly do a little more

Int Exh
.200 124 104
.300 174 134
.400 215 160 (about done here)
.500 211 168
.600 211 171




Some intake bowl and short turn work and some love on teh ehx could really pick those up. Wouldnt take much;still better than 20 yr old worked over parts.

1989TransAm

I saw this post on Speedtalk and it pretty well sums things up and I thought of this thread when I read it. By the way as Ron alluded to you might need a new tune to maximize the gains from your new heads. Here is the quote which I thought was quite good as the poster was answering a question about heads and airflow.

"It's not that easy. If you're supplying more airflow than the motor demands, it will only produce power on the top end. Flow will make you an instant hero, but velocity will make you a genius. If the extra flow in your port reduced the velocity, from what the motor wants, the motor will produce less power, and it will be at a high rpm. If the velocity is more than the motor can stand, it will be very responsive, but die on top end."

One might have to read it a couple of times but the poster is right on target. Its about the right air velocity.

dan_t

The Vetteweb artical mentions 430hp but then goes on to say trap speed was 105mph - this seems slower than I would expect if it was really making 430hp? Would you tend to agree?

James93LT1

I'm pretty sure that they are getting their 430hp on an engine dyno with no accessorys.

5abivt

are these cnc ported or as-cast heads? What is the chamber volume?

Running the same mph clearly means something is wrong. Sad to hear about the finish problems too. I opted to stay with LT4s over these because the really big eliminator (225/235) weren't finished yet.


Are your stock heads totally stock?

STEVEN13

This story sounds similar to (I think) WevsVette (Forum Member). He had cam with headers, auto, and went 12.40s changed to (again I think) AFRs and did not pick up much. Maybe he will chime in.

Regards,
Steve

hgh pwr

From his post I would think they are stock from trick flow, he says a lot of casting flash in the ports.

Should have had some porting before he put them on and he would have had a better experience.plus just a mail order tune not a dyno tune but he still picked up 2 tenths so with porting and a good dyno tune 11's should be easy.

radar502

Not building the right motor is one thing but the thing that is realy bad is the probs. with the heads casting flash and so on..You can send them back ..I can buy the wrong head but I do want to get a well build wrong head...Make a phone call people will tell you what you need .. Just ask, I do it all the time and most people are very nice I just ask I want to go very fast what do I need ... Just ask..I called some big shops and ask stuff all the time ,got lot's of good info...Don't just buy stuff...

cv67

Look at the exhaust #s vs stock

Wouldnt take much to really make those heads wake up though.
If you pull them off shoot me a pm

Even if you wound up with a 190cc+- head thats still acceptable

Casting flash wont hurt flow much its to be expected.
If it was super excessive would be curious to see a pic.


How much were these?

dizwiz24

The guys w/ the ported heads (ai, le, or comp. Ported afr) do the best.

Its money well spent, they clean up the castings

bjankuski

The heads flow quite a bit more then stock and should give you a nice performance bump. I would check your tune (Air fuel ratio at WOT) to make sure it is correct. A rich or lean tune can kill all of the gains provided by the heads. I would also check your timing advance and scan for knock retard. The trick flow heads may like less timing then what your tune is providing causing the engine to knock and pull timing and power. My experience with trick flow heads is they like 31 to 32 degrees of WOT timing and most LT1 have 36 to 37 degrees of WOT timing.

All combinations of parts require fine tuning to get the most out of them and most mail order tunes are only a good starting point to get you running but can still be improved upon.

hgh pwr

i agree 100 percent,needs some fine tuning before bashing the heads.