Which would be a better mod for me to get flowmaster cat back or the L31 vortec heads which would get better gains,how much hp would i gain with these heads, and do these heads work good with a 350 engine that im planning on rebuilding within a year or 2 thanx for the help

do the heads.

How about heads or headers?

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91 RS Conv. 305 tbi no cat. 16" IROC rims, whiteface guages. More soon.

i should do heads and roller rockers at same time

http://www.sdpc2000.com/cart.asp?act...d=277&pid=1120

check out that deal u think i should save and order

I was looking at that kit and was going to ask about it. if I did get that kit I would have to buy an adapter plate for the TBI right? Also would this kit make more HP than the Vortec TBI intake with L31 heads?


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1990 RS 305 TBI T-5
.5" turbocity spacer
Summit 14X3 OpenElement W/k&N
Custom Exhaust
MSD - Wires, Cap, Rotor, Coil
Bosch Platinum +4 plugs
Metallic Red w/26,000 miles

?

Heads, that sdpc2000 sounds like a good deal. I would think it would make the same hp as a TBI intake since they are both performer so same basic design just different mounting of the carb/TB. I would look at hood clearance.

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, Jon (350 TBI!)
91 Red RS w/grey int, sq stereo (Alpine v12, kicker solo, MB quart premium etc)

• Holley 670 TB unit w/ 1/2" spacer/adapter
• Edelbrock RPM vortec intake
• 350ho 330hp vortec crate motor
• 8" harm. balancer
• Stewart stage 2 water pump w/160 thermo
• SLP tri-y headers to full 3"
• Rebuilt trans w/ SLP shift kit
• Centerline 16x8's all around
• 36/24 mm sway bars
• Full poly bushings, even motor mounts
• SLP LCA and panhard
• Alston SFCs
• Edelbrock 3 point STB
• Global west steering brace aka wonderbar
• Eibach pro kit springs
• Bilstien high perf. struts and shocks
• All this and I still have AC

My websiteAny questions?

but would the tbi fit on that intake cause its not a tbi intake

A carb intake with TBI/adapter plate will make more power than Edelbrock dedicated TBI manifolds for sure. It has been tested. Not sure of the GM TBI Vortec manifold, though. Needs to be tested.

Where can we get things like that tested? I want to see speed shop dyno numbers with stuff like SLP headers vs edelbrock/hooker/etc and cam differences in hp & torque. Would be nice to try different intakes.

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, Jon (350 TBI!)
91 Red RS w/grey int, sq stereo (Alpine v12, kicker solo, MB quart premium etc)

• Holley 670 TB unit w/ 1/2" spacer/adapter
• Edelbrock RPM vortec intake
• 350ho 330hp vortec crate motor
• 8" harm. balancer
• Stewart stage 2 water pump w/160 thermo
• SLP tri-y headers to full 3"
• Rebuilt trans w/ SLP shift kit
• Centerline 16x8's all around
• 36/24 mm sway bars
• Full poly bushings, even motor mounts
• SLP LCA and panhard
• Alston SFCs
• Edelbrock 3 point STB
• Global west steering brace aka wonderbar
• Eibach pro kit springs
• Bilstien high perf. struts and shocks
• All this and I still have AC

My websiteAny questions?

while for sure some carb intakes with adapter can make more power, I'd be more worried about bad fuel distribution by using an intake that wasn't tuned for TBI like the Edelbrock TBI was.

yea i think i should get the L31 vortec heads and vortec tbi manifold too. Does anyone have this setup or knows about how much of a hp gain this would give my 89 305 rs. mines about 180 right now pretty slow neeeeed more hp.

Tas/all, the Edelbrock TBI unit was not necessarily tuned for TBI. It was made to "work" with TBI. I know this for a FACT!!!

Get the Vortec heads, Performer Vortec Intake and a SIS cheapo 204/214 .420/.442 cam/lifter kit (or the 214/224 .442/.465 cam if you are more aggressive) and you can make 300hp if you have 9.0+CR, good headers and exhaust on a 350cid. NOt sure if you said you have a 305 or not, sorry.

SDPC2000.com has a kit that has the heads, head gaskets, intake, intake gaskets, intake bolts, head bolts and rocker arms for under $700!!! Cannot be beat and the valve springs on them are good enough for those cams and up to 5500rpm intermitent use.

EDIT: Yep, 305. Get the 204/214 duration SIS cam and A NEW PROM to rid the EGR/change fuel/spark parameters a little, if you can live without the EGR that is. You should be able to get 220-250hp out of the motor this way with good rest of package, as I described above and it will be VERY DRIVEABLE!!!

[This message has been edited by FastBroker (edited March 30, 2001).]

yea i know about that kit for under 700 dollars but it doenst come with the vortec tbi intake it comes with the one meant for carb and then i would have to get an adapter plate for it. what do u think is better to get.

Did you read my above post? Get the non-TBI manifold with an aluminum adapter plate!!! The adapter is like 45 - 75 bucks

yea thats true, where do u get the plate from

also would this setup work good when i rebuild my stepdads 350 this summer so i can put the vortec heads on it

If you run L31 vortec heads on a 305 without milling the heads you will drop your compression ratio alot, probably a full point or more. This will negate the better air flow that the heads provide and you would end up with the same or less perfomance.IMO

Steve

so the chambers are 58cc instead of 64cc?

Holley sells the adaptor plates. They make a bunch. Everything from spreadbore, sqaure bore, TBI, to even ones with heating passages for emissions.

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, Jon (350 TBI!)
91 Red RS w/grey int, sq stereo (Alpine v12, kicker solo, MB quart premium etc)

• Holley 670 TB unit w/ 1/2" spacer/adapter
• Edelbrock RPM vortec intake
• 350ho 330hp vortec crate motor
• 8" harm. balancer
• Stewart stage 2 water pump w/160 thermo
• SLP tri-y headers to full 3"
• Rebuilt trans w/ SLP shift kit
• Centerline 16x8's all around
• 36/24 mm sway bars
• Full poly bushings, even motor mounts
• SLP LCA and panhard
• Alston SFCs
• Edelbrock 3 point STB
• Global west steering brace aka wonderbar
• Eibach pro kit springs
• Bilstien high perf. struts and shocks
• All this and I still have AC

My websiteAny questions?

is milling of the heads needed(58cc chambers?)

Is it needed? also how do you make a head go from 64cc to 58cc? How do you make it smaller. i thought milling removed material. I am a little confused. Should I not get the L31 heads than and look for some others that are non vortec. They will be more $ but if they make mroe power than that is what i want.


------------------
1990 RS 305 TBI T-5
.5" turbocity spacer
Summit 14X3 OpenElement W/k&N
Custom Exhaust
MSD - Wires, Cap, Rotor, Coil
Bosch Platinum +4 plugs
Metallic Red w/26,000 miles

Milling removes the material from the bottom of the heads. As a result the combustion chamber gets smaller. You have to mill the Vortecs .045" to get them down from 64cc to 58cc. If you don't get 'em milled they'll still work, but you'll get like 7.5:1 or some crappy compression ratio like that. Even after paying for the machine shop work the Vortec heads come out cheaper than aftermarket heads that will flow the same amount.

-Mark W.
'88 SC Camaro w/ 305 TBI

Ok this is all making sense now. What kind of machine shop would mill these down. Does it have to be a special shop or just any maching shop. Anyways If I had some instructions I could have my dad do it. he owns a machine shop but they rarely do automotive stuf.


------------------
1990 RS 305 TBI T-5
.5" turbocity spacer
Summit 14X3 OpenElement W/k&N
Custom Exhaust
MSD - Wires, Cap, Rotor, Coil
Bosch Platinum +4 plugs
Metallic Red w/26,000 miles

aluminum L98 heads are also a great choice. They are already 58cc, you save 40 lbs., you don't need expecive self aligning rockers, you don't need to mill them, they use 1000s of standard cheap intakes, they can take higher lift cams..... The only 2 downsides I can think of is no EGR and the price.

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-Tas
'89 Formula WS-6
[soon to have Hooker 1-5/8" 50 state legal headers installed]

305, TBI, auto, 14x3 chrome flat based open element with K&N, Milodon 160* thermo, functional Formula hood, cross-flow Flowmaster, '99z28 rear pipes and tips....

Super GRK_Taz World
EFI & Intake Options
AOL IM: superGRtaz

[This message has been edited by Tas (edited March 31, 2001).]

Uhg, this is starting to be a pain in the ****. IS there any heads out there that just bolt on. They don't have to be vortec, and if they aren't I will just get the TBI edelbrock intake. No biggy. It might cost more but will work better.

------------------
1990 RS 305 TBI T-5
.5" turbocity spacer
Summit 14X3 OpenElement W/k&N
Custom Exhaust
MSD - Wires, Cap, Rotor, Coil
Bosch Platinum +4 plugs
Metallic Red w/26,000 miles

Aluminum L98 heads ($900), 305 TPI heads(used$100), World Products S/R 305 Torqer heads ($729), Vortec 305 the (L30 heads) heads($200 used).

[This message has been edited by Tas (edited March 31, 2001).]

Edelbrock Performer centerbolt heads (60cc) $1099.95

how much would it cost to get the heads milled to 58cc and what gain would u get from these heads, what kind of increas in hp

$$$$????

I am as curious as 1989camarors. It is hard to find heads with 58cc. How much HP can we acheive with the 64cc heads milled down


------------------
1990 RS 305 TBI T-5
.5" turbocity spacer
Summit 14X3 OpenElement W/k&N
Custom Exhaust
MSD - Wires, Cap, Rotor, Coil
Bosch Platinum +4 plugs
Metallic Red w/26,000 miles

no one knows??

hey 1989camarors, I am thinking it might be easier to buy the edelbroak or holley TBI intake and match heads to it later when we get the money. It sounds to complicated to buy the L31 heads and then have then sized down properly. I would rather spend a little more and buy 58cc one that can be bolted on. I know vortec is supposed to be the best but I am sure TBI intake and heads that are non vortec will be just fine and still produce gobs o' power.

------------------
1990 RS 305 TBI T-5
.5" turbocity spacer
Summit 14X3 OpenElement W/k&N
Custom Exhaust
MSD - Wires, Cap, Rotor, Coil
Bosch Platinum +4 plugs
Metallic Red w/26,000 miles

Depends on who you know. Call your local machine shop and ask around in your group of friends to find a guy/shop where someone does business...