oxrabidus

I was wondering what the difference is between the l30 vortec heads (305...) and the L31 heads(350...) is? Is it just the size of the valves or is it a completely different head? If 1.94/1.5 valves are put on it will it flow the same numbers as the 350 heads?

Air_Adam

Its a different head - smaller valves, different and smaller chambers at the very least. I don't know if the ports are the same as the L31 heads.

Raw flow numbers only go so far, as far as making power goes. Chamber design is also very important, and the L31 has one of the best around, but I don't think the L30 head has the same chamber design.

oxrabidus

oh. well are the l30 heads still a good head? or are the 416(i think...the lb9 heads...) casting better heads?

Fast355

iTrader: (2)

The 059 casting 305 vortec heads are the BEST factory GM 305 casting available. They are also the fast burn chambers, just adapted for the 305s small bore. GM took the 4.3 265 L99 caprice head and cast it in a conventional coolant flow package. The 305 vortecs like practically the same advance curves as the 350. The flow from the vortec 305 heads is definately ALOT better than the old 081 TPI heads. The 305 Vortec made up to 230 FWHP @ 4,600 and 285 TQ @ 2,800. The Vortec series of engines ran smaller cams and more restrictive intake/exhaust than the TPIs did. Due to their truck nature, the timing and fuel delivery were far less potent as well.

oxrabidus

are the 059 castings rare? or hard to find? how much do you think it would make with a tpi cam and intake with a edelbrock base manifold?

Fast355

iTrader: (2)

059s are not very rare or hard to find. They came on many marine engines, truck engines, and Vans up to 2002. They are still being built today for 305 boat engines.

"TPI cam", which one? There are like 5 different ones.

oxrabidus

oh i dont know... i just asked to get an idea of how much more i could get with those heads... but i would probably get an XFI268 and put a TPI setup with a stealth ram on top... and port the heads to 2.00/1.60 race flo valves... something mild and quick to do... how much do you think that will make?

oxrabidus

do you think the vortec heads are better than trick flow 175 heads?

Air_Adam

IIRC, the TFS 175cc heads are designed for small-bore engines, like the 283 and 305.

They are basically just "scaled down" versions of their VERY NICE 195cc heads - smaller chambers (54cc), smaller valves (1.94/1.50) and of course smaller ports (175cc, and slightly smaller exhaust ports too).

The TFS 175cc heads are an excellent head, though "better" than Vortecs depends on your definition of "better". The TFS heads will bolt up to a traditional manifold, the Vortecs will not. The TFS heads can use both styles of valve covers IIRC, the Vortecs can only use centerbolt covers. TFS heads will already be machined for a higher lift cam and probably larger diameter valve springs as well. Vortecs will require this work be done if using any cam bigger than a stock L98 cam.

However, the Vortec heads initial cost will be MUCH less, as you'd likely be buying junkyard cores to rebuild. Rebuilding them and having some performance machining will add to the cost, but will still come up less than the TFS heads more than likely. The (typically) more expensive Vortec manifold required will probably offset that though.

You haven't said yet what engine you plan to put these heads on?

oxrabidus

i an gonna get a vortec 5000 engine...for a hundred bucks its not too bad i dont think... just rebuild it and port the heads a bit is my plan... then go with a set of trickflow heads and a couple more things... but for now a little bit of head work and probably a factory cam... like the l98 cam you suggested or if i could use an lt1 cam it would be nice... but nothing crazy powerful just something quick i guess you could say...

Air_Adam

The LT1 cam is probably really pushing the limit of those heads - if they are like the L31 heads, and they sound like they are, then they are limitted to around .450 or so valve lift. The LT1 cams are very close to that, if not over that, so I wouldn't try it.

oxrabidus

how much do you think it will make with the l98 cam a stealth ram intake and good tune? considering the heads are kept stock...

oxrabidus

if i get some better springs would that help to raise the max lift on the heads? or would i still have to machine the seat(i believe that is what is a big problem on the vortec heads...not sure though...) i read about some beehive style springs that can be put on the vortec heads with no modification and clear cams with up to .5" lift...if anyone knows which they are or if that is true/false, thanks in advance...

Air_Adam

You'll still have to have the valve guides machined down - thats what poses the restriction on lift. Since you'll probably have the heads off anyway, you might as well have them disassembled, cleaned, and crack checked. If they check out, have the guides machined down at the same time, I doubt its expensive. Get them cut to handle .550 valve lift and you'll probably be OK for most streetable cams.

Valve springs are matched to the cam that you use.

The bigger L98 cam (theres two IIRC) is a decent cam - with those heads and a Stealth Ram intake - thats the LT1-ish EFI manifold right? - should probably get you around 300hp, maybe a bit higher.

I assume you'd be using a set of headers and changing the exhaust as well?

oxrabidus

yeah its a two piece ram style intake... if its cheap to get the guides machined down then i will just go with the xfi268 cam with 1.5 rockers... full length headers and a good exhaust... dont know which one to get of either... suggestions would be nice... best bang for the buck... i an also gonna get total seal rings i hear those add power and reduce engine wear... and throttle body? which one would you suggest... 52 or 58 millimeter...with the manley valves i think it would be nice and quick...

Air_Adam

That 268 cam is a nice size, should be pretty solid in a street engine. Shouldn't be hard to get over 300hp with that cam.

As for exhaust - if its mostly a street car, I'd ditch the full length headers and get some good shorties. Full length headers are a big PITA on these cars. They make it hard to run a good muffled exhaust system because a Y-pipe is a PITA to make work with those style headers. Ground clearance is also a big issue.

I'd suggest a GOOD set of shorty headers and their matching Y-pipes. The Hooker 2055 set or Hedman 1-5/8 shorties (I cant remember the PN) are good sets. I have the Hedman headers and Y-pipe and I really like it. Fit well, lots of ground clearance, etc. Only problem with the Hedman Y-pipe is its 2.5" outlet, but it can be cut off and a 3" section added pretty cheaply. Thats waht I did. The Hooker 2055 headers are 1-5/8" and have a Y-pipe with a 3" outlet, so it would be the best set to use.

I have the Hooker catback on my car, and it sounds fantastic. Its not overly loud, but it has a really nice, deep rumble. Driving around normally its only a little louder than stock, but when you stand on it, it really barks.

oxrabidus

cool... i had seen the hooker cat back but never heard anything about it... at first i was thinking a flowmaster but it has too much of an annoying hum for me... either way what i may do is just get the piping and put one of those DNA mufflers or a hushpower two... with one outlet... make it kinda like a sleeper... plus i like the open kinda sound you get from a straigt through muffler like those... you think 350hp or close is possible? with all the stuff noted...

Air_Adam

350hp is probably obtainable from that combo if its tuned right.

I'd suggest the Hooker system, just because of its sound... its more "classy" than "look how loud I am". Flowmaster mufflers are like Steve Carrell yelling "LOUD NOISES" in Anchorman.

If you really want a cool setup, get the Hooker catback, and one of the $25 cuouts from Summit - the 3" piece. Add that where the Y-pipe connects to the catback. Then you can just pop the cap off anytime and run it like open headers. I did that, though I rarely use the cutout on the street. I use it quite often at the track though.

My opinion, the best exhaust for that engine would be:

- Hooker 2055 headers and matching Y-pipe
- Summit 3" cutout
- Hooker catback (get the system for the '87+ L98 cars)

oxrabidus

its not so much of look how loud i am, but i heard the hooker cat back, it does sound really nice... and does the cutout make a REAL difference? i mean i would probably order itr with the single exit muffler, just so i could get that "sleeper" (i guess you could say...) look... plus i would put turndowns at the end and keep it heidden behing the bumper cover...

and im digging the hooker headers plus y pipe...

and one thing i was curious about... could i get a harness and computer that goes with that motor and put a stealth ram intake on it? would it make a difference? or should i just stick with the TPI spped density/MAF (either or...) harness and computer...

oxrabidus

well i got the motor... it is from a 97 truck... it turns and only had about 70000 or so miles on it when it was pulled... the heads are 520 casting instead of the 059 casting... is there a big difference between the two heads?

Air_Adam

If I remember right, you can use a TPI harness, injectors, fuel rails, TB, and distributor with the Stealth Ram - basically just replacing the TPI manifold, and leaving the rest.

I don't know what to say about '520' castings, never heard the number. If its really a '97 though, its in the right range for the Vortec stuff. '96 was the first year I think.

The cutout will make a big difference in sound. When its closed, it will sound just like it would if you never installed the cutout, but when you pop the cap off, it sounds like open headers - because it is open headers. It can make a noticeable difference in MPH and ET at the track too. Did for me. Best $25 I spent on the car.

oxrabidus

well that is the last three numbers on the head... i will probably do the cut out... either way the heads are a temp thing i am gonna put the trickflow heads further on down the road... and some other nice stuff on it...

Air_Adam

Trickflow heads are the same port/bolt pattern as the traditional SBC, unless they have a new Vortec-style head I don't know about. If you did that, you'd be buying a new intake manifold as well when you change the heads.

What I'd suggest, is that if you go with Vortec heads now, get a set of GMPP "Fastburn" heads when you go for the Hi-Perf stuff. They are a Vortec style head, with Vortec style chambers, but they are aluminum with 210cc intake ports. They are a VERY nice performance head. Do that, and you will be able to use the Vortec style intake again when you change heads.

oxrabidus

210 cc... isnt that a bit big for a small 305? and i heard that for the money they are not as good as other heads on the market... but thats just what i heard... i really dont know...

Fast355

iTrader: (2)

The 520s still flow more than any other 305 head that preceeded them, including the 081. The 1996+ Vortec 305 was rated at 230 HP @ 4,600 and 285 ft/lbs @ 2,800. The truck engines were strangled by restrictive single cat exhaust, sound reducing truck intakes, and the tiny little cam they ran (191/196 @ .050). The engines output was further reduced by the spark advance settings that were required in the emissions controlled truck setup. The GM marine 305 Vortec was near 280 HP!

Vortec 305 heads are easily 30+ hp onto a stock engine.

oxrabidus

well how much better are the 059 heads to the 520 heads? if any... just wanna kinda get a feel for how much more or less power i can get from them... air_adam said 350 hp MAY be possible... it would be nice a lot better than my current 135 hp...my more realistic goal would be like 320 to 330... and what was different from the marine and truck 305 vortec?

Air_Adam

What may be the case, is that its basically two different part numbers for two castings that are basically the same. GM did much the same thing with the L31 heads - theres a '906' casting, and an '062' casting. But there is no real difference between the two heads. I've heard suggestion of the '906' having a more heavy-duty exhaust valve seat for use on heavier trucks (1-ton and up) but thats only a theory AFAIK. For all intents and purposes, the '906' and '062' castings are the same head.

That could possibly be the case with the '059' and '520' heads you are dealing with. They may be identical heads, but maybe one has the heavy-duty exhaust valve seats. That wouldn't make any difference for what you are doing though.

Fast355

iTrader: (2)

I don't know all the specifics on the 520s because I have never worked with a pair. But the numbers I have seen were substantially lower than the 059s. The 059s have a swirl inducing vane, nothing like the 187, 191, 193, 810s, but a slight one. I have heard reports of some 305 vortecs having swirl port intake ports. The 059s do not have swirl ports. Perhaps the swirl port is why the numbers I have seen on the 520s are lower.

oxrabidus

how much is substantially lower? think that 320 hp still possible? i always thought swirl ports were better? thats what i heard anyway...

oxrabidus

is there any way to remove this "swirl" from the port? If so will it hurt flow of make it better?

Atilla the Fun

Now that there's 29 opinions, here's the fact, from one who has tried them all. The Vortec 305 heads have swirl-ports, like the '88-'95 TBI. The best GM 305 heads are the '87-'92 TPI 225-horse 305 heads, with conventional ports. The TFS 175 heads are better. zz4 heads and Edelbrock Etec 170s are viable alternatives. I myself have exceeded 250 cfm from a zz4 head with a 2.00" intake valve, at 0.500" lift. These can be had the cheapest of the aluminum heads.

Fast355

iTrader: (2)

ZZ4 heads are nice heads for a 305.

ETEC 170s and TFS 175s are NICE, but EXPENSIVE.

TBI 305 heads have SWIRLs, NOT the 059s

TBI swirl ports





The BEST factory 305 heads are the 059 Vortecs, PERIOD. I have a set and they DO NOT HAVE SWIRLS, PERIOD, END OF STORY, for MY pair. They TRUMPED the 081s in HP/TQ EASILY and required less timing, which gave better fuel mileage.

As you can plainly see, NO SWIRLS are present in these 059s. The jury is still out on the 520s, because I have never seen a pair.



As you can see I had them on a running driving engine. Took this picture while replacing the thermostat housing that I had cracked. Coolant leak is no more, lol.

Atilla the Fun

In all fairness I've never seen that casting number until now.

Hog

12552520...97-up...305..........Vortec, truck
12558059...97......305..........Vortec, truck, 1.84"/1.5" valves

Both Vortec heads.

peace
Hog
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12552520...97-up...305..........Vortec, truck
12558059...97......305..........Vortec, truck, 1.84"/1.5" valves

Both Vortec heads.

peace
Hog

oxrabidus

i will take some pics to compare... i just have to get them off the engine... i read somewhere that vortec 305 heads somewhere around 416, or 406, or something casting heads.... which is 216@.500 " lift... don t know if there is any truth to that... but either way i am pretty sure they will make nice power... i am putting raceflow valves, 2.00/1.6, and a little porting... when i get the pics and put them up we can compare them, it will be a few days... thanks for all the feedback guys.
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how much more did power did the 059s make than the 081s on your engine?

oxrabidus

i took the heads off the motor, i cant tell if they have swirl ports or not, i tried to take pics but the lighting was crap, but i compared them to my 4.3l vortec hneads i had and they looked almost identical, i could not tell, but i will post some pics when i can get them...