You'd be way ahead building a 350 or larger engine.

The small bore/long stroke 305 isn't worth hot-rodding.

 

With all due respect for the 350, im staying with the 305 and it shouldnt matter what someone else wants to build. Lets PLEASE keep the "350" suggestions off the radar. I know all about it and I am keeping the 305 for originality purposes. Thanks.

 

I think you've identified what needs to be set up right. The TPI limits power in the upper RPM's so the cam and heads need to be selected accordingly. You can more or less figure that the 305 is going to cost around a 15% torque penalty compared to a similar 350 and go from there.

thirdgen.org has a wealth of information.
http://www.thirdgen.org/techboard/tpi/

 

With the 262 and a TPI setup it's going to be hard to make power past 5k.
I'd definitely suggest getting an aftermarket fi intake (one that flows much better) and getting the heads worked, or maybe even vortecs. Without good compression, you can't go much larger on the cam (keep it a roller if you do). If you have some extra cash, a forced induction cam and a procharger would be right at home on that motor, but the procharger unit is expensive.
With a good TPI 305 build (decent heads, cam, new intake, great tune) I could see 300 wheel hp, maybe 320.

 

Build the combo around the characteristics of the bore/stroke ratio. Don't shoot for a lot of RPM, keep the heads flowing well without going too big on the runners to maintain port velocity. I'll leave the cam selection to the experts, that will be dictated by your whole combo (gears,converter,static compression, vehicle weight etc.). If I had to guess at the cam, I'd probably go with a 218-224 @ .050 with a .500 lift at the valve.

 

Here's the tale of the tape.
1985 Camaro Z28 TPI 305 700R4 3.23 gears 3460# (t-top w/ out me in it)
26" tire
305 will be taken a part and rebuilt using the stock crank, scat I beam rods, KB silv o lite pistons, Vortec 062 iron heads or E tec's 1.94 1.50 or 1.55 valves, milled for 9.8 - 10.1 static, 0.038-.044" quench, ported matched stock base with AS&M long tube runners and port matched upper plenum, 52mm throttle body, 24lb. injectors, adjustable fuel press. reg., Dyno Dons headers (1 3/4" to 3" Y pipe, to 3" cat and cat back). 7165 ECM re pin, tuned with tunercat, Dig. Ignition, HEI, 160-180 stat, elec fan, pullies. K&N
Trans is stock 700R4 w/ trans go shift kit, corvette servo, governor and aftermarket stall matched to cam (lock-up) and external trans cooler.
Rear is stock 3.23 gears with auburn carrier.
UMI wonderbar and subframe connectors.
Stock appearance Z28 wheels and paint w/ stock graphics lowered with eibach pro kit.
A lot of this I already have, just not the engine stuff and converter as I waited to see what I was going to end up doing with it. Like I said, original plans were to make this car LQ9/4 powered with T56 or 4l80 but the swap in itself is going to cost about $5000.00 just for the engine, accessories and brackets, mounts, and x member, with ECU and wiring harness. Not including the transmission, clutch, flywheel, bolts, starter, cable, speedo signal adapter, and MAYBE a driveshaft. So in other words, as cool as third gens are, by the time the swap is done I could have bought an actual 4th gen and modded that. So, I see no point of building that. A 350 is a better engine, but this car is not for racing, its just going to be modded to hold its own on the highway and stop lights..like it SHOULD have gone from the factory. thanks. Maybe I can get some good cam choice advice. Its a factory hyd. flat tappet.

 

I think you have a good start - a few suggestions:

consider a set of AFR or L98 Vette alum. heads on the rebuild

1-3/4" header may be a little large for the 305- think torque and 1-5/8"

precision industries Vigilante lock up converter - expensive but huge improvement over stock

Are you sure its a FT cam? my '89 was hyd roller. UD Harold is worth chasing down, I had one of his UltraDyne hyd rollers in my 350 TPI.

 

An 85 engine would be flat tappet.
They changed to roller in 87.

 

Heck, even then you can't be sure. They put roller blocks in a lot of cars while still installing flat tappet cams. I think the Monte Carlo SS was like that through the end of its life cycle in '88. Friggin' GM.

 

Yeah, hopefully he will chime in, I guess I could send him a PM. I was wanting the 1 3/4 for the 350 swap later so I dont have to buy another set of headers, but yeah, a 1 5/8 would be better for a 305. I actually dont think I am going to do a 350 swap. I was going to do an LSx swap but for some reason I want to have fun with the 305 first.

 

I would PM Harold, he can be hard to get ahold of, but worth it, keep trying. He hangs out on Team Chevelle also, may have better luck running him down over there

 

The main reason enthusiasts choose the 302, 327 or 350 displacement SBC’s is that they share the same Large Bore Heavy 4” Casting that can handle Hi-Perf and dissipate heat without warping or blowing gaskets. The 4” bore permits the use of Larger Valves so the engine can pump more air. With the right Heads the 4.125 Bore the 400 block can really breathe.

Sadly the 76 to 2000 305 Block is one of the worst engines Chev ever designed for Hi-Perf. The Small 3.736” Bore Block and Heads are Thin Castings which limits Valve Size for Breathing and easily Over Heats when modified for Hi-Perf. The old 307 was a Sleeper with a 3.875” Bore and Heavy Cast Block that could handle fair size Valves.

If you think you can get 365 Hp out of a 305 without the Possibility of it Over-Heating and Blowing Gaskets or Warping by all means go for it. I personally would not waste my time or spend the money to Sup-Up a 305.

I would leave the 305 as is in the car, providing it still running and the gaskets are good, drive it, get a Descent Block and when it was done pull the 305 and sell it - More 305 have meet their demise the instant a water pump or rad fails then any Stock 375 Hp 327 which could run 20 miles without cooling fluid and not hurt it.

Don't take this as Bashing, I just want you to be aware if you intend to use a 305 ;o).

 

This is absolutely NOT true. I don't appreciate someone who thinks they know something they dont. Tell me Z15Cam, where did you get this information?

If this is true, then how are Stock Eliminator guys running 305's consistently in the 10's, 11's and 12's? Why are there dozens, if not hundreds of 305 powered S10's running 12's and 11's? Why are there countless 305's on thirdgen.org running anywhere from 9's to 13's? Preston owns the stock block 9 second IROC which IS a 305 GM block! The car is in a few magazines! Then there's Willies 89 IROC which is in the 12's, blown, then Streetlethals 11.40 second 305 with turbo's. Then there are quite a few more 305's that are blown just like it. Now, if thats so true then why isn't every 305 ever made cracked?

Do you know how many times a 305 has overheated since 1975? Gimme a break!

I am running the 305, to make a somewhat high revving small block (higher than it would rev with a 350 and certainly a 383) WITH TPI that will have max hp @ 5400-5600 RPM, and be a hoot to drive. I see it running mid 12's, being very drivable and appearing totally stock. It's mostly just for fun, as I dont want to change the car all that much.

GM's Joe Bertsch and Denny Davis (who was part of Zora Duntov's hi po group from the 60's) designed the 305 in 1973 to be a more efficient (hence the ideal bore to stroke ratio) on unleaded gasoline (leaded gas was being phased out). It was NOT designed to get the most HP, but neither was the 350! IIRC the 350 was made to be a more economical engine option for the Camaro, which, did the quarter in 16.1, 0-60 in 7.8. and that was with a 290hp rating! A lot of this info is available in GM's history book..
also...
The 350 was actually supposed to have MORE bore than 4.0". They were concerned with rings wearing flat spots in them, so they gave it the "off" number stroke because 350 ci was the demand from engineering group vice president Ed Cole.
ALL OF THIS HISTORY is accurate and trust me, I am not some "guy" who is new at engines, cars, repair work, whats been tried and most importantly racing. I am a certified auto tech, here in Austin, TX and have been for the past 9 years and also help out on some serious racing (sdba). I understand the 350 will make more power, but please understand I am looking for a quick 305 powered (probably 310 by the time its done) to resemble the best of what the original GM engineers were looking for. Better power, better parts, better ECU, better power, better mileage and thus a better 1985 Camaro Z28. I need people on the internet who would be interested to see what good 305 can do, help out with some technical information and ideas, and be supportive of the hot rod experience itself... I thought this board would be a good place... I may be wrong. Hopefully not.
I need* info on heads that posses the following; which deal out there seems to be the best. A .525-.550" lift spring is needed along with 225-cfm or more. 1.94 intake valves and 1.50 exhaust (maybe 1.55"). I am open to vortec's, aluminums or irons, stock or aftermarket. Also any vortec variance, like edelbrock e tec or RHS (I would LOVE more info on RHS Pro Torkers)
Flat tappet street/strip cams (remember we are camming a 305, not a 350, so any cam will "act" a little larger on a 305, than a 350...
Engine components, which pistons guys like around here, hypereutectic KB silv O lite's are looking good, but I wouldnt get passed some Mahle's.
Experiences on some past engines built... etc.. etc. You know, some enthusiasm, even a 305 deserves it (now and then)

Steiner, yes, I was under that same impression and was hoping to find a roller compatible block in my camaro, however, after talking with thirdgen.org, it would seem impossible to find one.. But then, the question is, the 1 pc. rear main seal block was debuted in 1985, but does that mean there are 2 years worth of non roller, flat tappet cammed blocks out there? That doesnt make much sense that GM would only change 1 thing, if changing an entire block...seems like a waste ya know? I will look for myself when I get in there...believe that!

 

Contact these guys they are the experts when it comes to TPI. http://www.tpis.com/ Forget about HP and RPMs. TPI=torque and torque is fun in a street car.You will be able to turn a 305 harder than a 350 TPI but the torque is where its at.And if you want to get real crazy you can put a 3.75 stroke crank in a 305 and make even more torque.

 

Contact these guys they are the experts when it comes to TPI. http://www.tpis.com/ Forget about HP and RPMs. TPI=torque and torque is fun in a street car.You will be able to turn a 305 harder than a 350 TPI but the torque is where its at.And if you want to get real crazy you can put a 3.75 stroke crank in a 305 and make even more torque.

There are quite a few more TPI places that TPiS, AZTPI, Arizona Speed & Marine, TPI Chips...etc. I am have looked at the stroker kits, and im still on the fence. I have seen the difference they make and its nice (stock TPI camaro with 335ci did 13.4 with just exhaust and a cam)... TPI IS for TQ, no doubt.. Thats why people do the 383 so, maybe the stroker kit would be worth it. 383 Strokers with TPI usually get 450lbs. or more. I wonder what the difference would be? I like some RPM...