Paging all of the smart guys.....

[jerrysta]

I am getting ready to buy the first of the parts for my motor project, which are going to be the Trick Flow LT1 heads. I am doing a 396 stroker and aiming for 500 horses and 11's.

Before I actually make this purchase I wanted to ask the members of this very knowledgable board if there is a better or cheaper alternative. The main reason for the head purchase is because I don't know if the stock heads, even when ported, can support the flow needed for my goals. Assume excellent port work becaue the guy doing it is good at it.

I'm really not considering the LT4 heads much because for similar money I can get the Trick Flow heads. So, it's either ported stock, or Trick Flow. I can obviously save a chunk of cash by using stock heads.

But......can the LT4 intake be used with LT1 heads?? If so, again the question of the flow comes into play again. Or, perhaps a ported stock intake will flow good enough.

I just want to make a smart final decision and thank you guys in advance for all of your help.

If I am wrong on anything above, feel free to set me straight.

The motor is about to come out.............

[Jeff95TA]

I thought the Trick Flow heads were intended for Nitrous or F/I applications.

[jerrysta]

Nitrous, stroker, or blower.

Mine is going to be a stroker.

[Craig 94 TA GT]

According to Trick Flow:
"

Let me shed some light on what this head is all about...

The flow data for this head is the same as the flow data for the standard 23* head. All we did was change the water jacket & some bolt hole locations.

The flow numbers you are seeing are for an "As cast" port, That means there was no bowl blending or short turn rework at all.

Yes, Our LT1 head is a thick casting, The port walls are .250" thick & the deck is .562" thick. (For a point of reference, The stock GM heads have only .160"-.180" port walls & a .400" thick deck surface...At least this is what we saw on the heads we cut up)

Just wanted to mention one other thing about port wall thickness. On ANY 180cc & bigger small Chevy head, the pushrod pinch point area is real thin. Our heads are no different.

Yes, This head has alot of potential:
With a light cleaning up I have seen high 260 cfm's.
With a decent porting, 280 cfm's are not hard.
With a real good port job, I have seen close to 300 cfm's.

Did I mention this head is capable of a 2.05 intake valve with out having to change the valve seats? We have had imput from some of our customers proclaiming 310 cfm's....(This is from the standard 23* head, Again same casting, different water jacket...)

No, This head is not a good choice for your average 128,000 mile Camaro with nothing but a K&N filter and a Flowmaster muffler.

Keep one thing in mind: This head is being marketed as a great choice with blowers, stroker cranks & nitrous. We are not trying to sell this head for stock rebuilds, Do not call me and say what a turd these heads are on your stock engine.

The reason why we did not offer the small 56cc chamber is because right out of the box, as cast, we could not get the head to flow the way we wanted. There is plenty of meat in the deck to mill heads if you so desire...

Now, If you are wanting to build a stock block LT1, supercharged street car, This is your set of heads...and they are only $1,295.00

In a nutshell, These heads flow enough air right out of the box, with out porting, to support up to 500hp.

By the way, Sorry for the slow reponse to this thread, I was out of the office from 12-8 to 1-2 for my Christmas vacation....

If you have any questions, Call me @ 330-630-1555 Ext:6324 or email me directly: akakiou@trickflow.com"

[jerrysta]

Thanks, that is some very valuable info.

[jerrysta]

With the flow numbers Trick Flow lists I do not see a big difference between them and a good port job on an LT1. Am I missing something? Would the LT4 heads and intake be a better bet?

Or should I stick to the stock heads?

[raroZ28]

If you must get new heads, I'd go with the LT4 heads. I heard nothing but crap about trickflow on cz28. Don't know though.

[jerrysta]

Will the LT1 heads work with the LT4 intake if properly ported to match?

[Craig 94 TA GT]

I would still stick with the LT1 heads.

Although AI is practially an LT1 porting expert, this is what they can do for a full port job to LT1 heads:
" This package has gone 10.20@135mph in a 3400lb F-Body with a 383, mild .620/.600" lift camshaft, bolt-on suspension, a stock reprogrammed PCM, and 3000ft+ Density Altitude! No other LT1 offering available can match the performance, longevity, or consistency this CNC head exhibits."

"Recommended Useage: Stock 350cid - 396cid shortblocks with piston relief/dish volumes of 5-16cc. With supporting modifications, manual stock shortblock F and Y-bodies can produce 395-435rwhp SAE corrected or 415-455rwhp STD corrected. For 440-475rwhp SAE pair this head with one of our ported intakes and a valvetrain upgrade. Whether it's a 400rwhp street sleeper, a brutal 10-second NA street car, or an outrageous 1200hp+ turbo engine this head is guaranteed to deliver!"

http://www.advancedinduction.com/AiProductsLT1.html

[fastTa]

Flow numbers are a good measuring tool IF they are taken for what they are. The more realistic potential of a cylinder head to support big power moves beyond the scope of "flow" and steps into airspeed and mean air velocity at upper-middle lift numbers as measured at the camshaft lobe. Big power is not made with huge ports and those popular peak flow numbers. Big power is made with a cylinder head that has a moderately sized and well balanced cross section and runner volume and moves a lot of air at a broad spectrum of lift at high airspeeds for better cylinder stuffing. Especially throughout the low and mid lift ranges where the valve actually spends much more time than close to a peak number on a cam card.

Additionally, people get wrapped up in comparing peak flow numbers. Let's say your cam card shows a intake lobe lift of .375". In a perfect world, that would net you .600" of lift at the valve with a 1.6 rocker. But, we don't live in a perfect world and there exists a reality called valvetrain deflection and lift absorption by a hydraulic lifter. This can knock .010" to .030" of lift right off the top leaving you with an actual measured lift at the valve of much less than anticipated by using ideal math (lobe lift x rocker ratio).

Given that, an LT1/4 head can support well in excess of 1000 HP with a power adder. There are lots of folks doing it. 500 N/A flywheel HP is solid reality with a fully ported LT1/4 head. A fully ported LT4 head can be made to flow in excess of 310 CFM with 2.00"/1.60" valves. Given that, a well built 396 with a good sized cam will easily exceed 500 N/A flywheel HP.

[Joe 1320]

Flow numbers are a good measuring tool IF they are taken for what they are. The more realistic potential of a cylinder head to support big power moves beyond the scope of "flow" and steps into airspeed and mean air velocity at upper-middle lift numbers as measured at the camshaft lobe. Big power is not made with huge ports and those popular peak flow numbers. Big power is made with a cylinder head that has a moderately sized and well balanced cross section and runner volume and moves a lot of air at a broad spectrum of lift at high airspeeds for better cylinder stuffing. Especially throughout the low and mid lift ranges where the valve actually spends much more time than close to a peak number on a cam card.

Bingo.

[jerrysta]

Thanks, guys. The knowledge of the board members never ceases to amaze me.

The guy building the engine said the same thing. Don't look just at peak flow numbers, they are a little misleading.

The only reason I am actually doing any research on the heads is because he has not done an LT1 yet. He asked me to check into available heads. He is usually building 500+ci big blocks for guys' older muscle cars. He's giving me such a break on the price that I felt responsible to at least give him some info on the heads to go with. So, now I have some info I can give him, thanks to you guys. Given his skill level, I am just going to use the stock heads because I know he will do great work on them.

Thank God for the internet that it can bring together guys with no knowledge (me) together with guys with tons of knowledge (the rest of you).

Thanks.

One last question....Should I buy the LT4 intake to use with my heads or just use my LT1 intake?

[fastTa]

One last question....Should I buy the LT4 intake to use with my heads or just use my LT1 intake?

It would make life simple to just pick up an LT4 intake manifold if you chose to use LT4 heads.

...But don't feel as if the LT1 casting cannot reach 500 HP. With a fully ported LT1 casting, moderate hydraulic cam (230-234ish @ .050", 110-112 LSA), and a 58mm TB, 500 ponies is easy.

Have you already picked out your rotating assembly components? Going splayed on the main caps?

[jerrysta]

Yes, splayed main caps because we are keeping my block. Don't know about the exact components because the builder is buying them for me. I know the crank is going to be forged, not sure about the other parts.

[fastTa]

Yes, splayed main caps because we are keeping my block. Don't know about the exact components because the builder is buying them for me. I know the crank is going to be forged, not sure about the other parts.

The reason I asked about the main caps is because I have noticed a few threads discussing splayed main caps. I have heard some discussion on this board and other boards about the possibility of the block webs being weakened by drilling for the outer splayed bolts. This just is not the case.

The Gen II LT1 blocks do in fact contain a slightly lower nickel content than their predecesor's Gen I small blocks, but the Gen II block webs are still more than strong enough to support a splayed outer bolt. Main caps that have an outer splayed bolt are much better at keeping the main cap registered to the block than a standard straight 4 bolt main cap.

One thing to note though is that most of the aftermarket splayed caps can cause an interference with the dipstick tube and/or dipstick. A company named Pro Gram makes a nice set of billet splayed caps that are appropriately notched to eliminate this problem.

Additionally a splayed cap does not allow for near as much distortion of the cap itself and therefore keeps the main bearing bore extremely accurate. It also allows for a more precise line boring process since the main bores are lined honed while the caps are registered and torqued in place.