I have a friend that has a 1980 Vette with a 350. It has about 110000 orignal miles on the motor. He is not satisfied with the power, so he asked me to build him an engine for around 2500. Here is what I have in mind. Let me know if it sounds like a good deal

1. GM Performance parts SBC Vortec Cast Iron Cylinder heads, 1.94/1.5 valves, 170cc intake, 67cc combustion.
2. GM Performance parts Dual Plane Vortec Intake manifold.
3. Speed Pro 360HP Engine Kit from Scoggin Dickey, with cam, forged flat top pistons, and everything needed for the bottom end rebuild.
4. Edelbrock 650CFM carburator
5. Eagle I beam connecting rods

Now all I really want to know is if that is a good setup. Will it make 330-360HP. Scoggin Claims thats what the Kit will make. I can't think of a cheaper way to build an engine that makes more power than what he has already. Thanks guys

Tyler

 

Well to be honest, just about any 350 can be made to put out more power than that lame L48 he's got. 8¼:1, 929 cam, 882 or 624 heads, and tiny exhaust manifolds, in a 3900 lb car, pretty much adds up to "slow". Those cars are known as "plastic pigs" by the partisans of other brands of cars, with excellent justification.

Anyway....

That cam can be improved on, especially with Vortec heads. Those heads flow dramatically better on the intake side than the exhaust; and so, benefit dramatically from cams that help out the exhaust side, by using a bigger lobe.

I'd suggest the Comp XE262 or 268, or a cam with similar specs from another top-line cam mfr.

Other than that, it's just typical basic stuff in the kit, should work fine.

360 HP is just about double the HP he has now. With the right cam choice instead of the inappropriate one in the kit, you can get over 400 HP out of the motor itself; and probably better gas mileage and street manners too, all at the same time.

 

The carb and rods seem like a waste of money. The stock q-jet will do fine, and ARP bolts in reworked stock rods will be fine.

If you really want Vortecs, might as well get them upgraded with better springs and what not. The SDPC upgraded Vortec kit http://www.sdpc2000.com/cart.asp?act...2172&pid=89534 has everything but the valve covers. Don't forget the Vortecs need self-aligning rockers and centerbolt covers.

 

Thanks guys. Speaking of the cam I have the Xe268 in my IROC right now. I guess what I was looking for will those heads be a damn good choice for the price they are???? I know the pistons and rods are good. Cam we can adjust. Carb, if the quad is good, what CFM is it. I don't know that. Why not the Edelbrock?? He would be happy with 350HP, but if we can make 400 with out much more money then, let me know what we should do. Thanks

Tyler

 

The Q-jet will be around 650-750 CFM

And it's all personal opinion when it comes to the type of carb.

I know die hard chevy people who wouldn't put anything but a Holley on a motor, others a Edelbrock, and others nothing but die hard Q-jet fans.

I'm not a fan of the Rochester Q-jets because of the famouns Q-jet 'stumble' they have when you get into it. I had a Carter Quadrajet (before they sold it to Rochester) which didn't have this problem on my GTO.

The bad thing about Q-jets are, alot say they have to be rebuilt after about 70-100k miles as the seals dry out etc etc.

There are two edelbrock carbs out, a Q-jet replacement, and an AFB replacement.

 

Just wanted to give my .02 cents. I have the xe268 comp cam with the vortec heads with 1.6 rock arm. I have to say the motor pulls really good I beat up on impala ss all the time. With my build up I killed my 200r4 and broke 3 starters before I went with a mini starter. So look forward to rebuilding your transmission and getting a mini torque starter. Oh yeah I had headers with 2 1/2 exhaust on the car with no cats the car is loud and drinks gas. That motor is getting pulled and being replaced with the l98 turbo or ati set up. I think I was bitten by a sbc :hail: :hail:

 

I had a Carter q-jet that I made stumble/bog by improperly adjusting the AV tension. Rochester q-jets aren't any more prone to that than Carters, it's all in the adjustment.

Never heard that about q-jet seals and rebuild requirements. More to do with gas quality and usage than anything else.

 

There's no such thing as a "Carter" Q-Jet. The Q-Jet is a Rochester carb, that came out in 1965. Carter didn't "sell" the Q-Jet to Rochester. That's all messed up.

The deal is, there was a fire in the Rochester plant where they built those carbs, that knocked it out of production. I don't recall exactly when it was; seems like it was the late 60s or early 70s sometime. Carter at that time had lost some OEM contracts and had alot of spare mfg capacity, and Rochester contracted with them to build Q-Jets for them. That lasted for several years. Ones mfd in Carter's plant say something like "Rochester Q-Jet by Carter" on them. There is little if any difference of any significance to which plant they were made in; as I recall, the tooling all got shipped from Rochester's plant to Carter's plant, and the process and material specs were all the same, it was just executed inside of somebody else's 4 walls.

Production returned to Rochester sometime in the mid 70s. All computerized Q-Jets were built in the Rochester plant.

 

On all Q-jet's I've seen they say Rochester on them. The one on my GTO didn't have Rochester stamped anywhere on it and it even said Manufacturerd by Carter Carburator.

*EDIT* I stand corrected, the plant did burn down and Rochester did have to sub-contract the carbs to Carter, but IMHO the Carter's are better than the Rochesters.

They have a totally different part number than the Rochesters do though, the majority are the 4GV's but the Carter's are like QJ-xxxx for the number.

 

No, it's not wrong. That's exactly what happened. The reason the ones on some cars say "mfd by Carter" is because, as I described, Rochester subbed out production of them to Carter for a period of time, after their plant was damaged.

They're still all Rochester Q-Jets, the carb was still designed by Rochester (div of GM as opposed to an independent supplier to all OEMS such as Carter), and Carter didn't "sell" the Q-Jet to Rochester.

Carter did sell a few of them under their own brand name; that doesn't make the Q-Jet a "Carter" carb.

{edit} I happen to have one myself that says that, installed on my 74 454 Caprice convertible; and probably a handful of them on my shelf as cores too, since the particular period of them in question happens to cover the era just before somg took over. Certain of them from that era are the easiest to turn into a performance carb as a result. It's still a Rochester carb even though it was made by Carter. It happens to be a 4MV (V is for divorced choke), unlike the 4MC (C is for integral choke) in your pic. The model 4G isn't a QuadraJet, it was a smaller carb easily identifiable by having 4 fuel bowls and 4 individual vents that all point together in the center of the carb. It was replaced entirely by 1965, and IIRC in some 64 models, by the Q-Jet.

There's no detectable difference that I've seen in 30 years or so of modding them, as far as "quality" or "better" or any of that, that's traceable to them being either made at the Carter plant or the Rochester plants. Since, as mentioned above, the tooling and everything else is the same.

 

Whew, we've chased quite a rabbit.

Agreed, whether manufactured by Carter, Rochester, or Edelbrock, a q-jet's problems/benefits are a function of the model and condition, not the name above the door where it was made. The Edelbrock q-jet was supposed to be "fixed", but my experience with two different ones is that there really isn't much, if any, improvement over the Rochester production effort.

As to q-jet or Edelbrock Performer (what I assumed was meant in the original post by "Edelbrock 650CFM carburetor): There would be no performance improvement going to the Performer over the q-jet. As stated, q-jets will flow up to 750 CFM and support 400 HP easily, so there wouldn't be any power gain. Economy would probably drop, as the q-jet is one of the best carbs available for the compromise between performance and economy. If you don't have any carb when putting a project together, the Performer could be considered, but if you've already got a perfectly functioning q-jet (or one easily made so with rebuild and/or tuning), then don't spend your hard-earned dollars (or even somebody else's) for a different carb.

 

Ok, so with the vortec heads and intake, XE268(which I have in my 89 IROC), headers, flowmaster, forged flat tops, and q-jet. would that be a good set-up for my friends 350 build for his 80 Vette? What do you think it will possibly Make for HP???? Thanks


Tyler