knight123

iTrader: (4)

Posting here from general engine to see what the TPI crowd has to say..

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?

Here is the goodwrench engine and cam specs:
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.

darbysan

Don't see any reason why this would not work fine for a DD. I would probably want a dual pattern cam rather than a single pattern (222/222), but I think with a 114 LSA you should be OK. I'd say go for it.

knight123

iTrader: (4)

Hey thanks for the response! Cams are not my thing at all. I kinda understand the basic way to spec them but being able to say if one would work ok in a fuel injected engine is another let alone with SP heads from a 305.

adam.binkley

that sounds like the combo i'm putting together! i have a L05 with L05 heads and a TPI intake. and i can't decide on cams. but i'm limited to flat tappet cams.

knight123

iTrader: (4)

Cool, I've been doing a lot of reading on this here at TGO and some people seem to say that these "lower class" heads have potential. The cam seems to be the wild card with a build, if you can match the cam to the heads it could be the difference between good and OMFG great based on some dyno's I've seen posted. That match could be as much as 30-40hp additional - now that also means you have to have the intake and exhaust to match which is why I was going to port the TPI and drop some headers on it.

adam.binkley

Thats what I've heard as well. I'm not hoping for great but half decent and running would work for me. This motor is going into a truck when its finished. with long tube headers, good exhaust and as for the intake. who knows.

92RSTPI

I wouldn't waste your time with those swirlport heads (found on LO3's and LO5's). Find some better heads. Those don't flow at all and you'd be wasting your time.

knight123

iTrader: (4)

Yeah, I've been trying to figure out that. Seems most people posts are in your camp and say just get something better, then there are some lengthly posts where people have used these heads on various builds and got some decent numbers. The hangup for me is I plan to keep the TPI and keep the usable power at 4k and below so getting a head good to 5k might not really help me.

This is the post that I've been reading on that side of the house:
https://www.thirdgen.org/forums/tbi/...-headflow.html

I think the safe route would be to do as you say and just get something better which could give other options as well later but I'm kinda interested to see what would be the result doing this too. Hmm.

blacktopbandit

im building an l05 350 with 305 TPI heads and tpi top end set up but i have nooooo idea what cam to buy

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?

92RSTPI

From my understanding, you can make a stock l98 hit 350-400 with bolt ons. This is essentially what you are building, so that seems doable if you have the right exhaust, TB, and ECM tune.

knight123

iTrader: (4)

Yeah that's what I had read etc on a bunch of builds so I'm hopefull the TPI won't limit me too much and single pattern cam will work good with those heads and intake.

ninetyone

iTrader: (2)

Maybe if you include better heads as a bolt-on.