Hey everyone, need some help.
I have a 1986 Trans AM with a once rebuilt 305 that is just crapped out. I want it replaced...
I am looking at about 4 options that i need some input to guide me to the best option.
I have 5,000 bucks to spend restoring this car...that is motor and paint. about 3500 for motor and 1500 for paint.

I am looking at the ZZ4 crate motor from GM those are about 3500 by themselves

The ZZ4 fastburm 385, but those are about $4000 alone.

The crate 350 H.O. 330 HP and getting some better heads, baseplate and runners. The crate is about 2200 and that would leave 1300 for the extras

Or buy a used 350 block and build it up to my liking. My concern with this is I dont want to have to redo this again anytime soon and am concerned about the durability of the used block, would the saved money, if any, be worth it??

I am looking to end up with 300HP at the wheels and 270lbs to 300 lbs of torque at the wheels aswell. currently I have full 3" exhaust and a single flowmaster, with a high flow cat. THe tranny is a 700-r4 with a shift kit, only about 20,000 miles on the tranny (max).

I have never done anything like this before and need some guidance. I live in California and that means it has to be completely smog clean and operational. All smog equipment is currently on car and it will pass if the engine is running. Will all of this fit if I use some SLP headers, stock plenum, runners and air fittings??

Thanks,
chris

 

Chris- let me make a suggestion, if I may. To keep costs down, but still go with new might be a pricey proposition. You'll need about 350-360 at the crank to lay 300 to the rollers. That's ZZ4 territory. And it's still not emissions legal since the aluminum heads on that motor don't have an exhaust crossover for the EGR system. Yes, you can add one externally to make it functional, but it won't look stock and you might get failed on the visual. Of you could just run it with an EGR valve that LOOKS correct but is, in fact, non-functional.

Same deal with any engine that uses Vortec heads, plus the added complication of having a totally different intake bolt pattern than your existing intake. I don't think even the Scoggin Dickey Vortec TPI conversion kit is technically emissions legal in CA (but you might want to check with them)

I'd highly recommend an aftermarket performance engine, even though they are usually built for used cores. Something that uses heads that will keep your EGR functional and/or carry a CARB E.O. as an emissions legal replacement part. A 350 with a modest emissions-friendly cam should be able to be had for about $2500-3000. That's for a long block that is ready to accept your intake, exhaust, accessories, etc.

Even in CA the only things you REALLY have to pass are the visual test and it's gotta pass perfume out the tailpipe. They have no idea if you have a 350 in place of a 305, and they have no idea if you changed the cam or not. I don't think that even in CA they go so far as to trace block and head casting numbers, measure valve lift, etc. (Although I could be wrong about that!! CA is emissions **** land.)

 

When you say aftermarket high performance motor, are you talking about starting with a ZZ4 Long block and then adding "other" (I havent found a set yet) heads that will accept EGR hookups, Holley Ram TPI system with baseplate, Roller cam and rockers, and SLP ceramic Headers. This is the setup that I am thinking of purchasing unless you have another suggestion, but through research everything listed will have a CARB number and should give the ZZ the air it needs to breath. Stock TPI seems to have a hard time breathing well enough for any more than modest increases over stock. As far as the coincidentals like dist., coil, injectors and the like...it does not seem to be to specific. The only thing that is certain is that this is not cheap, about $4400 for everything listed, but I am sure that will pass $5k before it is finished. Better be worth it, I love this car.

Thank you for your help,
please let me know what you think.

chris

 

For "round one" I would keep the TPI. It's going to be challenging enough to get the new motor built to cost and get it back in the car and running. No, the TPI won't make quite 300 to the rear wheels BUT you can put an engine under it that's capable of more, when you want to change out the intake later.

If you're swapping from a 305 to a 350 TPI you'll still need larger injectors (stock are 19lb in a 305, 22lb in a 350 TPI) and most people building a modified setup just go straight to 24lb or larger units and then get a chip burned to handle them and the modified engine all in one shot.

If you change the intake you'll STILL need the larger injectors and custom chip PLUS the cost of the intake. Your budget will be stretch pretty tight.

As for the Scoggin Dickey Vortec TPI kit.... IF that is emissions legal that would be a good way to go. It comes with a special base plate that will bolt up to the Vortec heads but will take everything else from your current TPI setup. You could buy a complete GMPP 350HO long block (330HP), the Scoggin Dickey kit and basically use the rest of your stuff from there. It would be a strong combo. It would feel like you put a second engine under the hood compared to your old 305.

If you really want to go with a different intake then just buy a complete aftermarket long block, spec'ed out the way you want it that uses a set of heads with a common intake bolt pattern. I wouldn't buy from GM unless you think the extra cost (and warranty in some cases) is worth the extra money.

The Holley Stealth Ram is NOT emissions legal to my knowlege.

 

I disagree, 300 rwhp shouldn't be that hard with a TPI. It's going to take some planning to do it, but it is possible.

9.5:1 compression 350 CID with the Scoggin dickey vortec TPI head package and a hot cam should get you 300 rwhp pretty easily. Especially if you use the larger runners and port the plenum. You will need a good set of 24 lb/hr injectors to feed the thing as well as a good computer tune. The biggest parts of getting the thing smog legal will be the tuning and sneaking it past the visual inspection.

 

300 RWHP? Are you going by the 357hp (I think 357) Vortec TPI motor they have? What kind of times do you think you'd see out of that setup?

Another question:

With everything ported, base, plenum, and SLP Runners, what's the powerband of a TPI system? Still around 5k?

 

Actually, I forgot that SD made that engine. I didn't see it when I looked at their site. Anyway, if you go with an estimated 15% driveline loss (some say more, some say less), 357 Hp would equate to like 303 at the tires. In a 3600 lb car, 12.9-13.1 should be possible depending on how you workt he suspension. I think the TPI will make more bottom end torque which would make the car really fun to drive.

With all the ported goodies, the TPI will still run out of steam between 5000 and say 5500 rpm. It's not so much the amount of air that the thing can flow, it's the path the air has to travel. Above 5000 RPM, the intake pulses start getting backed up because they have to travel down 21 inches of intake runner. Now on an LT1 manifold, a TPI motor will rev to 6000+ with relative ease and still be wanting to go higher. GM accomplished this by using 3 inch runners, but if you look at the specs, the TPI makes like 10 ft/lbs more torque than the LT1 does even thought he LT1 makes more HP. Of course, the LT1 also has aluminum heads, quite a bit more compression, and a better cam than any L98 ever came with, but the L98 still makes more torque. Torque equates to fun.

 

So you're saying:
350
Vortecs
SDPC Intake
Hot Cam

That will be a 12 sec car? Maybe with SLP runners, a bigger cam? I don't know...just seems too easy to me.

-Corey

 

It's not a bad combo for a good running street car. You can get the entire engine and the EGR kit from Scoggin Dickey for about $3450 plus freight. All you have to do is switch the engines, bolt on your runners, plenum, and throttlebody, get some bigger injectors and get a chip done. This would be the easy way to go.

If you want to guarantee 12's, ditch the TPI for a Stealth Ram or a converted LT1 manifold and a better set of heads. The LT1 conversion may be easier because you don't have to modify the underside of your hood like you usually have to do with the Stealth Ram.

If you're really feeling adventurous, you can do a custom EFI setup using a single plane MPFI intake and a 4 bbl throttlebody.