slohand

Hi guys,

as you can see i have a 350 crate vortec engine from scroggin. it'srated from at 357hp. i have just about maxed out the potential and am thinking about changing the heads for more hp.

while looking at the scroggin site they have the exact same engine as my crate with just the fastburn heads added and they rate that engine at 430hp. they do use a carb vs efi but can fastburn heads really make 70 more hp than the iron vortecs?

just in case you wondered, the compression is the same, cam is the same, rockers are the same.

opinions would be appreciated, i wouldn't mind spending 1100 if i could pick up 70 hp but that just sounds a little high to me.

i did call and ask scroggin about this, they really didn't have an answer.

Sonix

iTrader: (1)

I wouldn't think it's 70HP. What heads are on your motor now?
What cam?

hmm, "downgrading" to a carb shouldn't help pick up much HP, assuming the injection setup on the motor currently is adequete. What is it now?

That sounds kinda fishy to me...

xpndbl3

iTrader: (5)

put in a XE274 cam or the roller equivalent and expect the same power output easily as the fastburn motor. Furthermore, a TPI is not optimized for that combo and a carb and intake will make the most HP over FI always. Unless the numbers are within .5% of each when it's done, I've never seen an article or test done where FI made more power than a simple carb ever.

slohand

my engine and that engine are both running lt4 hot cam with 1.6 rockers. both at 9.6 compression. everthing is the same except i have the modded iron vortecs and those are the aluminum heads.

also, been told a carb is good for about 25-30 hp but even so, 40-45 hp from just these heads?

that's why i am asking, it sounded funny to me too.

thanks for the input.

DENN_SHAH

iTrader: (1)

if the fuel injection is set up right for a certain motor, i doubt your going to see much better power numbers from a carb on that same motor. after all, how many top fuel dragsters or funny cars have you seen with a carb?

Sonix

iTrader: (1)

uh, I thought most dragsters ran carbs, on giant tunnel rams?
anyway, I don't think 30HP is right. If you're replacing TBI or TPI sure, but if it's some aftermarket high end unit, nah.
Vortecs -> fast burns? Iron-> AL (same CR ratio), I think you'd LOSE a few ponies down low, and not really gain anything actually.
That's just my humble opinion though. Same CR going to AL will lose a bit of HP. Bumping up the CR is where you see the gain. Anyway, I wouldn't bother, there's probably other ways to get some HP, rather then $1100 on heads to replace your vortecs.

matt_p

Carbs can thank the tried and true single plane intake for making great HP. Put a billet 4barrel and injectors bungs on one and HP will be probably favor the one with the better tune.

slohand

i really believe the fastburns would generate some increase in hp. they do have larger valves and i think the ports are a little larger but 70hp? it just doesn't make sense.

i agree it would problably change the power curve up into higher rpms and cost a little torque. even with that in mind if it did make another 70 hp on the same engine......well..........they would already be on order.

xpndbl3

iTrader: (5)

i doubt you'd gain anything worth the expense on a TPI motor. basically none since the tpi is the bottleneck not the heads. In fact with it being aluminum heads and no bump in compression for their better heat transfer I just don't see it being worthwhile at all.

PROPHET69

Not that i'm an expert but can i ask a stupid question that MAY shed some light...When you dynoed your ride, did you do rear wheel horses test or did you actually do an engine dyno like scroggin did?

84L69TA

Its SCOGGIN...not SCROGGIN

Matt_P: Thats a good looking Camaro!

joe350

Runner length and port/valve size as they relate to your cam and intake will play a much larger role in your over all power generation than the material your heads are made out of. It is all about getting more air in and getting it in faster. Aluminum heads mostly allow you to increase the compression (or boost I guess also) of an engine without detonation and without some other significant design difference should not gain any power over iron heads.

slohand

both the engines are flywheel HP measured by scoggin. (look ma no r)

maybe that is the "problem" with the test. one is a tpi engine and the other was tested with a carb. kinda makes me wonder if instead of the hsr i have i wouldn't be better off with a nice carb set up. decisions decisions.

if anyone else has insight into this conundrum feel free to chime in.

Confuzed1

iTrader: (4)

So, it gets 70 more HP at what rpm? Bet it's over 4500.

xpndbl3

iTrader: (5)

the vortec head combo with a carb makes more than the 357hp, that's rated with a tpi setup on it. This is where the 70hp gap comes in since the fastburns are rated with a carb setup on it. Anyway you look at it the tpi setup is costing you hp, if you're running a hsr then you're making more than 357hp if it's tuned properly.

Damon

I just went and checked out both motors on their website.

Are you SURE they use the same cam in both motors (LT-4 Hotcam?). The website does not say which cam comes in the 357HP TPI/Vortec engine. I'd be a little surprised if it was the LT-4 Hotcam they put in the 430HP carbureted Fastburn engine. The hotcam is 218/228 on a 112* LSA with .525/.525" lift using GMPP 1.6 rockers. That's maybe a smidge aggressive for a TPI setup. Are you sure they didn't use a milder cam like maybe the ZZ-4 cam?

Regardless, I don't think heads alone would make 70HP difference, apples to apples. The difference in the intake probably accounts for a significant portion of the difference.

Orr89RocZ

iTrader: (20)

the zz4 uses L98 aluminum heads which flow less than vortecs and it makes 355hp

that same motor with fastburns makes 385hp.

that fastburn 385hp with the LT4 hotcam is rated at 430hp...
with even a bigger cam, it is rated at 465hp from scoggin dickey

TPI is killing that hotcam and head combo on that crate motor. with a carb manifold, it should make near 380+hp.

And the fast burn crate motor with LT4 hot cam with that TPI setup should make 375hp. i cant imagine much more. fastburn and LT4 hotcam like to rev over 5500rpms, where TPI likes near 4500. thats alot of HP that your missing out on.
those fastburns have 210cc runners which are too big for a low reving 350 motor. thats why the vortecs make so much power, they keep smaller runners to keep velocity up. they really are a good match for TPI setups.

DENN_SHAH

iTrader: (1)

i didn't notice you have a TPI intake, as this is in the general part of the boards, when you mentioned EFI, i was thinking something other than a LTR TPI.
yes, i could see that much more horsepower from a carb over a LTR TPI intake at higher RPM, especially if your talking about a stock LTR TPI intake.

with something like a LT1 intake, i feel it would be a somewhat different story.

slohand

yes, the vortec tpi that i have, the one scoggin sells, has the lt4 hot cam with the 1.6 rockers. i agree it's not the best match for ltr tpi, but it is still in there.

the 357hp they rate this engine at was based on stock chip w/350 injectors. the only change was edlebrock runners and their base. (headers & 52mm tb too) i spoke with Brian who ran the test mule for this engine back before i bought it. he told me that edlebrock runners were only good for 5hp on the dyno. he also told me they did not gasket match anything and the plenum was not ported either.

hard believe the tpi is kiling hp that bad but it sure looks like it. that is why i bought the hsr. i was thinking about doing the heads when i put it on but from the responses i am seeing it does't look like it would be worth it.

as for where the hp is, well no doubt either a carb or hsr will change the curve of both hp and torque. i can't find a chart listing/showing the curves for the 430fastburn. just hard get my mind around the tpi killling this much hp. on the tests i have seen the hsr genrates about about 40 extra hp so that would leave maybe 30 hp from these heads? is that possible? certainly sounds more likely.

orr89 if i am reading you correctly, it would seem the fastburns would only pick upabout 18hp with the tpi setup. thoughts? and would you expect the difference to be bigger with the hsr?

thanks guys, great stuff here!!

Orr89RocZ

iTrader: (20)

the fastburns would probly make 20 more hp i think. they flow alot more than vortecs but what hurts them is the 210 runners. i think that in itself will hurt the power numbers. the flow speed will be slow and you'd loose alot of lowend power.

TPI wont like it too much since it doesnt flow enough at high rpms to take advantage of that 210 runner. a 383-406+ would like it. OR a miniram or HSR on that 350. i think the gains from goin from TPI/vortecs to HSR/fastburns would be HUGE with the tune.

i find it hard to believe that motor made 357hp on stock chip. it should run with stock chip but FAR from optimal. most i could see would be 270whp which is more like 310-320 crank with stock tune and injectors

vwdave

Running aluminum heads instead of iron has some benefits.

-They are more resistant to detonation, you should be able to bump the compression or bump the timing some and gain power on that principal alone.
-Alot of aluminum heads weigh some 40lbs less (set) than Irons.

Thats all other things considered equal, like springs/valves/runner designs...etc

slohand

that is the number they advertise....357hp 416 ft lbs of torque with stock chip at the flywheel. as i said they did use a 52mm tb, headers, and the edlebrock runners but that was suppose to be all.

i can't help but wonder what scoggin could have gotten with a good chip, ported plenum, and some gasket matching. when i pulled mine off i was shocked at how much the new gaskets blocked the ports. can't imagine how the must not only restrict air flow but also disrupt the air flow as well. it always pays to check the details.

since i am going to put the hsr on, you wanna give me a wag about how much the fastburn heads would add? of course if i was goint that route i could always have the vortecs ported. just courious about your opinions.

Damon

Aside from the TPI system itself being a restriction I think I just found another part of the "missing horsepower." A STOCK CHIP??? Man, when you change the basic breathing characteristics of an EFI engine by that much the stock tune is probably FAR from optimal. That also might explain why a runner change didn't get them much. Once you're out of tune improving breathing further is not likely to help things much- it only takes you even further out of tune.

slohand

outstanding!!

no doubt the stock chip restricts the output from the modded engine. carbs have no such restriction.

i read an article where the picked up about 20-25 hp form a chip. that would put the 357 up to maybe 382 then if you figure about 30 hp from the ltr tpi restriction, well guess what, were are at 412 which strangly enough is EXACTLY 18 hp. that is right in the ball park of where the difference between the fastburn and the iron vortec has been surmised.

talk about hiding in plain sight.

thanks guys, think i'll save the 1100 for something else. so what percentage do you charge?
----------
oops should have said 18 hp from the 430 the fastburn engine is rated at.

thanks again!!

Damon

I get it all back twice over in good karma.

slohand

ya karma's great, it just stick to my teeth real bad.

Orr89RocZ

iTrader: (20)

see their you go. lol with alittle port matchin the TPI intake stuff, and chip tune i could see maybe 20 more hp. still tho, near 380 crank hp from a vortec headed TPI hot cam combo is kinda optimistic. i would have said 360-370 well tuned... but i've seen stranger things..havent seen any dyno results on that crate motor yet. but vortec heads do make power.

fastburns are great heads but not for TPI. if you want more power outta that setup, look into portin that TPI setup or gettin different runners and port the base. HSR tho will be killer on that combo. the heads will be fine

slohand

Hey Orr,

yep that is why i bought the engine. once ur into HP it's worse than drugs. gimme more!!

i have been VERY happy with this set up. stock ls1s are no problem, not even the ss with cat back etc. only one of those who i couldn't take was an 02 ws6 with exhaust, headers, heads, cam, and still don't know what else and the ol girl didn't do that bad. yes i was getting pulled but not by a whole lot 75shot and it would have been a different stroy. we only ran to about 75 it may have gotten worse as we pushed 100 but in a 45 zone, well common sense stepped in.

if scoggin (see still no r) hadn't run it on a dyno i would have wondered too.

still would be interested in your guess on HP with the hsr and fastburns.

Orr89RocZ

iTrader: (20)

yeah it does sound like a stout motor! i'd want one with 383 cubes tho LOL

that hotcam does make some good power for what it is. LT4 motors are said to make 425 with the hotcam and i have heard ppl say thats alittle optimistic. most i been seein is 350whp well tuned which is more like 410crank. my buddies LT4 CC306 cammed 97 SS camaro was said to have put down 372whp. i only seen it go 12.5's at 110mph tho which is only 1 tenth faster than the kids new 02 slp SS which put down 333hp but traps 110 as well. so i think either something was wrong or it didnt put down 370whp. lol so i think the hotcam is only good for 340whp (390-400crank) on average with LT4 heads and LT1 intake. fastburns and HSR wouldnt be too far off. my guess is 340-350whp or 410-420 crank hp. the fastburn crate is rated at 430hp tho, and HSR is close to that of carb manifolds on flow..maybe 10hp difference.

slohand

383? wuss..........427!!!

i was honestly quite pleasantly suprised by this motor. it has about 35k on it. when it goes or when my ship comes in, which ever is first, i want to go with a 406 or even 427 sbc.

i dunno, on second thoughts maybe just put a blower on this, should end up about the same.

you sound like there could be better cams for this vortec setup, suggestions?
keep in mind this has the 1.6 rockers. now, i don't want to completley kill torque, stop lights are just to much fun.

what kind of gears is the 97 running, also tranny? could that be why he isn't shaving the extra time off?

also, Brian at scoggin told me he was running corrected 12.5s in the 1/4 on a very consistent basis with this engine, 3.73 gears and 3k stall.

isn't it amazing how we now talk about 12.5 like it's not all that great anymore? from someone who lived throught the terrible late 70s and early 80s that was faster than any car made at that time. ain't technologh great?

xpndbl3

iTrader: (5)

9s are fast, everything else could be a daily driver

Orr89RocZ

iTrader: (20)

the 97 ss had a 4.10 rear with T56 up front...launching 5500-6000rpms. thing was killer off the line. the guy drivin was a good driver and he could only get 12.5 out of it.

Lt4 hotcam isnt bad of a cam but it was designed for a short runner intake. there probly are better grinds available that would suit TPI characteristics.
i did find dyno results of that scoggin TPI motor with stock runners. made 265whp and 373tq. ran 13.4's at 102 bigger runners probly could make 280whp. but running 12.5's on that is pretty good

camarodarrell

A magazine tested a 350 with a hotcam and vortec heads with a carb. On an engine dyno it made 420 hp. Only a 10 hp difference from the fastburn heads.

Orr89RocZ

iTrader: (20)

thats wierd... cuz its a solid 30hp gain from the zz4 to the fastburn 385..both motors running same cam/bottom end

i guess your reachin the limits of the LT4 hotcam. both heads must be adequate to produce the best results from that cam. on larger motors or more aggressive setups, i'd bet the difference of the fastburns would be noticeable

zz4monte

The vortec heads are worth 15hp on a zz4.So 10-15hp sounds sounds about right.Of course with a bigger cam and higher rpms the fastburns would make even more in the top end.My friend has a zz4fastburn and the torque difference in the lowend is noticable.The my zz4 pulls harder then his fastburn but my car is also 420 pounds lighter but the fastburns heads are better on a bigger motor 383+.The regular zz4 has much more torque.I would just run afr 180cc on a 350 daily driver for that amount of money or just get the vortecs.The new vortec 175cc heads (not the old 170cc are supposed to be worth 10hp over the 170cc.Your better off with a smaller combustion chamber for a daily driven 350 170-195cc.Also the vortecs flow better on the intake on the low lift areas.The fast burns only shine after .400 lift. I really think some 170cc edelbrock e-tecs would be a good choice for aluminum if you want to save a little over the AFRs.