I have a stock lg4 305 with a 700r4.Now i want to put on a diffrent top end cam,lifters,and heads.The motor only has 22,000 on stock rebuild,trannys coming out and in with a 350 turbo fully built with shift kits and 2500 stall converter.Was thinking of vortec 350 heads but im open to sugesstions.And im going to stick with the quadrajet setup with some headers but should i go with long tube or shorty headers.

 

shortie are easier to install, lt1 cam forget the 350 heads on the 305 way to much time and money for outcome. look for a nice set. if your going vortech go 305 vortech plus port polish.

 

Vortecs would be a good choice- many have used the 350 Vortecs on the small bore 305 with success around here. I know little about the 305 Vortecs so I won't comment but I haven't heard of anyone rushing to them for performance applications on the boards I vist.

Vortecs (any kind) require a Vortec specific intake manifold. Since you're upgrading the intake, that's a gimmie anyway. Just thought I'd point out that you can buy Summit house brand intakes for a lot less than the name brand ones. And they're all exact clones of the latest generation Weiand intakes (they ARE Weiand intakes but with a Summit logo on them instead of a Weiand logo). Only for use with squarebore (Holley) carbs, though, not for your original QJet. Here's one, for instance:

http://store.summitracing.com/partde...8&autoview=sku

 

everything sounds good to me.I'm going with the vortec 350's and still want to keep my q-jet setup.So if anyone nows an intake that works with the q-jet and vortec heads please let me know.thanks for all the replies so far and looking foward to some more input.

 

Vortec 350 heads will be a great choice for the 305, they have slightly larger valves, and flow pretty well with a good chamber design. You'll want to mill them down some, I believe the chamber size is 64cc stock, that would result in pretty low compression on a 305, you'd like 56-58cc chambers to keep the compression up. Damon is correct, you'll need a new intake specific to vortec heads, any of the "Performer RPM" knock offs would perform well. With a Qjet application, you might be able to use a ZZ intake from GMPP, those are also just knock-offs of teh performer rpm, but use the spread-bore pattern, I'm not sure if they make those for vortecs or not, but I would suspect so.

You mentioned a cam too, how wild do you wanna go? With a 2500 rpm stall you could tolerate something in the 210-220 duration, maybe keeping the lift under .485 so you don't need to mod the heads to tolerate the lift. I'm running a Summit K1102 cam, if I had built the motor I would have went one stage higher with the K1103 (http://store.summitracing.com/partde...&autoview=sku), its a 214/224 duration @ .442/.465 lift. I'm assuming flat tappet based on the year of the car, is the motor a rebuild, or a new motor. Roller or flat, you've got options. If your thinking cam, think gears as well.

The Q-jet should be a good choice as long as its working right and setup properly. Long tubes would be a better choice then shorties, but that depends on how much work you want to endure. With good heads and cam, with a good intake and exhaust, the LG4 can be made to run in stock to mild L98 range. I think with the cam I mentioned above and vortecs you could see 13's if you've got good rubber and gears, sounds like the tranny is already built well.

 

its a stock rebuild 22,000 miles rearend's coming out in with a posi diskbrake whats a good gear set to go with.Also the 700r4's weak so a 350 turbo fully built is going in with raceing gears and shift kits.any other mods i might need feel free to let me know.Thanks all!!

 

I like 3.73's for a rear gear, but I've got overdrive, which your not going to have with the TH350, so it depends on how important fuel economy is to you. If you don't care about the gas mileage, 3.73's, or even 4.10's would work good, depending on the cam you go with.

 

looking for fair gas mileage car might endup being a daily driver not sure yet.Building car for my 18 year old sister's first car/(my presonal play toy).so what do you think would be a good setup.

 

How is the idle on the K1102 Summit cam in a 305?

Also - what valvesprings did you use?

 

The K1102 is pretty tame. I idle pretty smoothly right at 600rpm in drive. There is a very slight chop, but once everything is warmed up you'd have a hard time telling it from a stock idling motor. A 350 would tame it even more. It pulls well from 3000rpm to 5500rpm on the 305, but if I had built this motor, there would have been a K1103 or other equivelent in there. That still may be the case some day. The valve springs are whatever came with the crate motor, GM stockers I'm sure. No major float issues yet, but I don't explore rpm beyond 5500 with this setup.

 

Incorrect. The only Vortec intake that has a spreadbore mount is the Performer (and the GM version made by Edelbrock). The Vortec RPM does not come in a spreadbore version. And, the ZZ3/4 intake is for old school heads - the ZZ3/4 uses Vette aluminum heads, not Vortec heads.

Okay, I guess I'm not clear about whether Edelbrock knock-offs for Vortec heads have an RPM-like version for spreadbore carb mount - I would never consider using one of the knock-offs.

IMO, shorties are the only choice for ease of routing and any hope of ground clearance. Unless the gal mentioned below is very aware, ground clearance is going to be the only way the pipes are going to survive.

Keep the TH700, then. The TH350 is a very, very poor choice. I know they made millions of them, but that was before fuel economy was an issue. If the TH700 you have is weak, rebuild it; or find an '88-later core and rebuild it. Either way, you aren't going to want more than 3.23 gears - a good choice for decent performance without too much of a penalty in fuel economy.

Keep the CC q-jet. It's a great street performance choice, nearly impossible to beat for fuel economy, and has power capability well beyond the 305's.

Have you talked to your insurance agent about this little project for an 18 year-old? I know what mine thinks.

 

I'm pretty sure they make a zz4 for vortec heads, I'll have to look around. If the Q-jet is to be retained, a zz4 spreadbore for vortecs (if it exists) would be a great choice.

I would definetely agree there, as I eluded to, long tubes are optimal from a performance standpoint, but present signifigantly more work and consideration.

Exactly. You've gotta get to decent power levels before you need to really worry about the 700R4's handling capablities, and any type of daily driver will benefit quite a bit in the mileage department with a overdrive and lockup converter.

 

No such thing. The ZZ4 has 113 heads; which are the traditional port location (not Vortec), with the 86-back bolt angles.

As Five7 pointed out, the only "big brand name" Vortec intake with a Q-jet flange is the Performer, or of course the GM-branded version of the same casting.

If this LG4 has dish pistons, then with the Vortec heads and STOCK deck clearance, it will have about 8.1 - 8.3:1 compression. If it's been rebuilt and has the usual and customary .020" ADDITIONAL deck clearance, the CR will be around 7.8 - 7.9:1.

I don't think it's a very good idea in that case.

If this LG4 has the STOCK flat-tops still in it, the CR will still only be 8.6:1 or so; and around 8.3:1 with "rebuilder" flat-tops. Still not great, but not as dismal as dishes will create.

I think a MUCH better idea would be to pop the heads off and do a little port work; or, get another pair of them (416 casting) and do your work to those.

 

Yea, the vortecs require some work to make them work.

I was thinking of the GMMP performer RPM knockoff that fits vortecs, I guess its not the "ZZ4" intake, but some other part#.

 

No such thing.

The GMPP intake is a Performer, not a Performer RPM; and not a knockoff. It's the same thing AFAIK. Just like the current ZZ4 intake appears to be the same thing as a Performer, looks like out of the same mold even, except with a GM logo instead of the Edelbrock one cast into it.

Likewise, there's no Performer RPM Q-Jet, either.

 

I'm getting my performer and performer RPM's crossed. I should know, I have a ZZ3, which is idential in every way to a Performer but like you said, a Bowtie cast on the front.

 

Right...

And I goofed as well:I should have added, "for Vortec heads".

 

I've got a complete Vortec topend if your interested. It includes:

New Topline Vortecs. Larger 2.02/1.6 Valves. Pocket ported and prep'd by CFM. I have the flow #'s and they flow a lot more air than stock. High lift Flat tappet springs. These heads have larger spring pockets and screw in studs mounts.
New Self giuded 1.6 RR.
New Prof Products Air Gap Manifold. I'll throw in a set of gaskets. This manifold was mounted on a motor but never ran.

Also, I have a Comp XE274H cam and lifters. It was installed in a motor but never ran. Also have a retrofit Crane Hyd.Roller. PN119821. Both would be a good cams for the heads.

I'll sell the heads and rockers seperate if you want to invest in a Qjet manifold. Drop me PM if you're Intersted.

 

2.02 intake valve isn't going to work well with a 305. Sounds like a good package for a 350.