knight123

iTrader: (4)

Ok so here it goes:

I have a 305 TPI car that I drive now, engines got about 5K on it, rebuilt by the PO.

I also have a goodwrench 350 /290hp engine complete with about 60k on it

I have a 305 TBI parts car, the engine siezed but the heads were rebuilt about 30k miles ago and assuming they are still good.

I was thinking after researching this idea:

- remove the current 305 TPI engine
- remove L03 heads from siezed engine
- put L03 heads on goodwrench engine, this will raise compresson and allow me to use the TPI.
- home port the TPI base and line expand the runners for more flow
- shorty headers, car has 3" factory Y pipe and 3" cat back dynomax
- take old 305 TPI engine and swap into parts car as TBI to get it running so it can be sold as a running car... or maybe another build?

now I know the TPI will limit RPM to about 4500 and so will the L03 heads, but I'm not sure how the hotter cam in the goodwrench 290hp will play with the L03 heads or the TPI. Since my car is MAF I'm assuming tuning will be minimal if at all as long as I swap the injectors, chip, ESC, new flywheel and knock sensor.

The only things I need to buy is a flexplate $20, gaskets $80, ESC $20, knock $20, refirb 22lb injectors $150 & 350 chip $120 assuming I don't use that money to buy tuner software.

Based on what I've read, the motor should be a torque monster. I'm hoping for 250rwhp and maybe 400lbft of torque. The car is a cruiser and I rarely rev it over 4krpm

I am engine savy but not a builder by any means which is why I'm asking questions here. So if I spend about $400 would I be better off after this stuff with a car that runs stronger but still keep it's manners for the wife?

torque_is_good

where is the option of putting the 350 into the parts car?

why yank a rebuilt 305 TPI? If it runs great then why mess with it?

knight123

iTrader: (4)

Well, I have thought about that, current TPI engine needs new injectors (PO never changed them, idles a little rough, leak etc) so they need to be replaced. If I buy the 19lb injectors then I would have to buy another set if I wanted to drop the 350 in. If the 350 might give the car a little more grunt the swap is not that hard at all and I can save $150 by not buying 2 sets of injectors so I'm trying to see if I might gain something by doing this. Once I get a feel then I can go buy stuff but I wanted to hold off until I know more.

Winter is coming so the car will be off the road and I'm looking for a project to keep me busy until the spring.

knight123

iTrader: (4)

here is more data on the goodwrench and specific cam data:

GMPP 290/350 HORSEPOWER HP 290 SPECIFICATIONSHorsepower:290 HP @ 5,100 RPMTorque:326 FT/LBS @ 3,750 RPMDisplacement:350 C.I.D.Bore / Stoke4.00” / 3.48”Max. Rec. RPM:5,100 RPMComp. Ratio:8.50:1Heads:Cast Iron, 76 ccValves:10093027 - 1.940” I, 14095451- 1.500” ECamshaft:03896962 Hydraulic Flat Tappet Camshaft Lift:.450” I, .460” EDuration @ 0.050":222° I, 222° ELifters:05232720 Flat TappetConnecting Rod:10108688 Powdered MetalBlock:10066034 - 4 Bolt M., Iron, 2-piece S.Pistons & Pins:12514101 AluminumCrankshaft:Cast Iron Nodular, 3.480" StrokePiston Ring:12507985Rocker Arm:10089648 - 1.5 Ratio Stamped SteelHead Gasket:10105117Oil Pump:12555284Oil Pan:10066039Ignition Timing:34° BTDC total @ 3,000 RPMFuel:87 OctaneSpark Plug:R45TS, Gap @ .035 For Points Distributor or .045 For HEI DistributorTechnical Notes:1) Distributor with melonized steel gear MUST be used with steel camshafts or engine damage will occur. GM recommends their HEI distributor P/N 93440806 if you need a complete distributor and not just a hardened gear.
2) Use ported vacuum for vacuum advance when setting timing.


03896962L-82 330HP, 350 Hydraulic Flat Tappet
This hydraulic flat tappet is used on the 68-81 L-46 and L-82 Corvette. The duration at lash point in degrees (intake/exhaust) is 312/312; duration at .050” tappet lift (intake/exhaust) is 222/222 and maximum lift with 1.5:1 rocker ratio (intake/exhaust) is 450/460. Valve lash is zero/zero and lobe centerline is 114 degrees.

torque_is_good

I'm not part of the "always 350 crowd"

if the 305 was in fact compeltely rebuilt, then I'd focus on getting that running well. It has a roller cam, is rebuilt and can give you years of reliable service

mess with the parts car

knight123

iTrader: (4)

Thanks, I'm really on the fence about the 305, don't get me wrong it pulls nice, passed emissions, it'll light the tires and chirp 2nd. I've been researching what to do to add some more ponies to this engine and with few exception most say go 350. There are a few builds I've been watching for 300hp 305 but to me it looks like I'd have to spend like $1k - $1.5 to buy better bolt ons which is not in the budget. Lets say I did spend that money though what is the drivability of a built 305? I want something that has good manners until I lay into it so no real lopy cam, no super loud exhaust and keep the TPI etc.

knight123

iTrader: (4)

Been thinking about the cam and swap more, I guees it comes down to if I had to spend the same money on the 305 where could I be vs if I swap and spend that money on the 350 for now does that set the stage for something better in the future?

Aaron R.

If you keep that 305 TPI stock and just perform basic maintenance (like replacing stock injectors with new or rebuilt stock injectors) you will have much less trouble in the long run. The car will be more dependable and you will spend more time driving and less time fixing stuff.

You start monkeying around with a lot of modifications and the headaches start. The header bolts keep backing out, The new carb/injection setup can't seem to be tuned quite right, etc.

Unless you like constantly tuning and working on your car, I would just keep it stock and enjoy it the way it is.

dimented24x7

iTrader: (2)

The GMPP 350 is ok, but the heads leave a lot to be desired. I had that engine, and it was luke warm at best. The low head flow and compression really hamper the power output. Itll be better than a stock 305, but probably not much better than a stock L98. If you use some ported stock heads (NOT the LO3 ones, put those on the 305 instead if you pull it) or aftermarket heads with a good cam itll make some good power.

There is another issue with that engine in that it uses a flat tappet cam. With a flat tappet, you can only run so much lift and spring pressure. Probably you wouldnt want to run much more cam than whats in there, along with stock or near stock springs if you want to use the engine day in and day out as a daily driver. The other option is to go a retro-roller, but that gets kinda pricey.

knight123

iTrader: (4)

Good point, I like working on cars as a hobbie as long as it's not my DD. I have another car for that so the Firebird is really a toy. That said though I don't want to be working on it all the time. I kinda like doing the big stuff in the winter and then be able to drive the car all summer. If I don't have anything to work on I start looking for something to do which usually means buying a new car or something like that - which then gets my wife upset and the cycle continues

knight123

iTrader: (4)

More good points, a head swap to something else is not out of the question, I was thinking of the L03 heads since I had them. I don't want to go Vortec because I want to keep the TPI and the base is too expensive to justify. I've been looking at some heads, casting 193's can be had for about $300 all rebuilt and ready to go but they have the 76cc chambers still. There is also the 113 casting (L98) that has I think 58cc chamber and decent flow. I don't want to put more than $500 in heads on this.

Been searching and found these online: http://stores.ebay.com/J-and-C-Cylin..._fsub=12923467

seems there are some castings not discussed on TGO out there.

I've also been looking at the cams, retro is a lil pricey so depending I might be better off selling this engine and getting a roller engine (missed my chance by 1 day and so got this complete engine for $100 so..

dimented24x7

iTrader: (2)

The flat tappet is ok for the long haul provided you use stock springs and good lifters like the GMPP ones, which is what it probably already has in it. That and some 5W-40 or 15W-40 diesel oil and ZDDPlus additive will help ensure it lasts. The life of a flat tappet in inversely proportional to the spring pressures it has to endure, so Id probably use the older style grinds with the less aggressive profiles if you want to swap it.

Some L98 heads would be good to top it off. Maybe with a little porting to help clean them up and get a bit more flow, but nothing extreme is needed since its a low revving TPI motor.

dimented24x7

iTrader: (2)

Actually, I was looking at the cam specs, and with a TPI motor, you may want to stick something smaller in there. Summits 1102 or 1103 grinds would be a good choice. 1102 will give better fuel economy and low end torque torque while 1103 will help the top end out. For an engine with stock TPI intake and stock L98 heads, Id use the 1102. It will be a good match.

knight123

iTrader: (4)

Thanks, those cams are fairly cheap even when you add back the cost of new lifters it's well under $200! I've been looking on CL for some used L98 heads but have not found any yet. It seems that finding a decent flowing head with the small chamber to bump compression and fit TPI is a challenge (for a good price) Going Vortec I guess would be ideal but that instake base cost doesn't make sense.

If I update the TPI intake with better runners and port the base would that change the cam you'd recommend?

knight123

iTrader: (4)

Well, just an update to the thread. I went and got a set of used L98 aluminum 113 heads, roller rockers and hooker 5022 headers. All used but in good condition with less than 1000 miles on all of it. Between Craigslist and local swap meet I got everything for $400 total.

These heads should raise my comp to about 9.5 depending on head gasket used, flow much better etc. I can bolt my TPI to it after porting too so I think I should be ok for decent power.

I'm hoping for 320hp at the crank, you guys think it doable?