Hello,I am a new member,but I have been reading the threads and doing searches trying to find a simple answer but I just get more confused.I have a 1988 Chevy truck yes a truck! I know its not a Third Gen but you guys seem to be the experts on this TBI stuff.It is a 5.7 and it has seen better days engine wise.What I would like to do is replace it with a stock Vortec long block using the GM TBI intake and all of my stock TBI parts.My question is will this combo run on the stock tune and will I need anything extra other than the external EGR plumbing kit? Thanks for any help in advance.

 

https://www.thirdgen.org/forums/tbi/...tec-310-a.html

Generally speaking it is a very common performance swap. A custom tune will be required.

//RF

 

Would there be enough air flow difference from the LO5 to the L31 to keep it from starting and running so I could data log and get some base line info? If it needs changes would I be better off to buy chip burning equipment or just invest that money into the EBL that is flash capable? Please take into consideration I would only be using the equipment one time as I am not planing any further mods, well other than a better exhaust system later down the road.

 

If I assume 7747 ECM with a stock ASDU calibration it will be good enough to start L31. The L31 uses vortec heads and due to their efficient chamber design (looks like a heart) do not require too much timing at WOT - 32 to 34 deg max. On the other hand conventional heads (I do not know what you have on your current LO5) needs about 34 to 36 deg. Does not sound like much, but it is a world of difference. Performance wise both SA tables and VE tables will have to be optimized to match L31 improvements over L05 - cams are different, heads, intake. In other words tuning will be required, but it is not too bad as displacements of two engines are the same. You also may want to consider to improve your fuel delivery system (aka fuel pump, FPR) as LO5 was rated around 210HP and L31 275HP. Stock fuel pressure (13PSI) is insufficient to support L31 full potential - but a simple increase to about 16 to 18 PSI should be able to support additional HP using existing LO5 61 lb-Hr injectors. You may want to do this once you complete the swap, but do no be surprised to find this out.

As for equipment - I am very partial (you may want to seek another opinion on this subject) - get EBL Flash. You will not need another piece of tuning hardware for your truck. I also use TunerPro-RT for bin file editing (Excel and WUD for analysis). IIRC in EBL package you get vortec optimized 'starter' bin file. Yes, the price for EBL may appear high, but after screwing around with adapter sockets (still do occasionally), flash chips, burners the EBL is light years ahead. Plus there is support and documentation - from Rbob and other users. Check out the 'telenovela' Tuning with EBL thread! Before dropping a dollar and starting wrenching make sure to ask questions - planing and understanding challenges is a key to any successful project.

//RF

 

I just want to make sure you realize he will be ADDING spark advance with Vortec heads. TBI heads require less advance than Vortec heads. TBI heads make peak power with 28-30* of advance.

 

Thanks guys this is starting to make sense now.It is a 7747 with ANLW calibration,the LO5 is stock with swirl port heads.I think I get the direction you guys are going.The L31 from what you are saying flows better,so more air = more fuel and the chamber design is better so more timing is possible without detonation.More fuel pressure will give me more fuel to a certain point before an injector change is required. So I will need a better fuel pump and a adjustable pressure regulator for the tbi unit I have seen the threads on this now I see why the sa and ve tables would need adjustmenets to correct the blm and timing across the board even though the engine is the same displacement. To compare it to what I know big heads big valves cam and headers used to equal big carb now it means you need to reprogram

 

Fast
I have never played with a pure stock LO5 - my error on SA. Every TBI equipped 350 that I have played with wanted to have more SA at WOT. These were 70-80's conventional smog heads and TBI was retrofitted onto these previously carburetor equipped engines. And yes I just looked at ASDU calibration at WOT (PE enabled) 28 deg of SA is called for.

Back to discussion - Check Moates website for TBI Vortec reference calibrations.

//RF

 

When you figure in the 9.81 offset it is only pulling 19* @ WOT....That is ALL the timing a STOCK TBI engine gets. Under 20* @ WOT. Most trucks used as a truck with swirl ports can tolerate 26* of timing under sustained WOT.

For reference we just did some timed acceleration runs in my brothers little 1980 C10 truck that has a 305 with 059 305 Vortec heads and got the best power with 32* advance all in by 2,900 and 10* initial.

http://www.youtube.com/watch?v=VxJmvWAlIQQ

 

and who said that 305 can not make power!

 

With the two of us in the truck and all the junk it was easily pulling around 4,500 lbs on that run. I think it gets up pretty good for a high mileage spare parts engine.

 

Thanks for the input guys.This project is well underway I was just trying to hash out what to do about the induction system.I have three options as far as heads go,the LO5,the L31 or a set of 5.0 TPI heads.I have completed the short block it is the L31 four bolt main with summit flatop pistons.Based on what I learned from you I think I will buy a programer and some eeproms and give tuning a try,also I think instead of the GM TBI intake I will just go with a 4BBL carb intake and an adapter plate.This way just in case the tuning does not work out for me I can just throw the Flamethrower in it and the Holly on top. Still open for suggestions,Thanks

 

What are the specs on the cam ???
Did you made sure that your 062 heads can handle more than .450 lift??

//RF

 

I have two cams.I have the L31 cam and I have a LT1 cam from a 1994 Fleetwood.I checked the lift at the lifter and multiplied X 1.5 the Fleetwood cam seemed to have more lift so I used it.I checked the valve clearance with NO. 1 at overlap and a Felpro head gasket they do not hit the piston.The Specs. are best I can tell (I 418 ) (E 429) I do not know how to find the duration.I also made sure that pin sticking out the front did not hit anything.

 

Basically, since you have heads off it is always a good idea to improve springs for potentially higher lift cam down the road. My favorite spring upgrade, surprisingly, comes from GM - yellow LS2/LS6 Beehive springs 12499224. I sourced my last set from SDPC for about $55. You'll also need Comp Cams retainers 787-16 and umbrella style valve seals - Sealed Power Part # ST2015 (hard to find, used on 86 Daytona 2.2L turbo - try RockAuto). The heads may (most likely) require a minor seat machining to accommodate these springs. Talk to your expereinced machinist. Check out this link:
http://forum.grumpysperformance.com/...php?f=52&t=181

This is a relatively low budget upgrade, but you will get you a set of heads that can accommodate (safely, with margin) valve lifts up to 0.525". Vortecs do not need more valve lift as airflow in the Vortec heads begins to decrease between .500″ and .550″ valve lift. Vortec head true performance is at low lift flow which gives more area under the total flow curve. That's where valves spend most of their time during engine operation. Valves spend much more time at .400″ lift and below, which is where the Vortec outperforms most other SBC heads. As always, it is a good idea to check valve to piston clearance (use soft play clay).

//RF

 

Yes from what I read about these heads it indicated they are excellent low to mid rpm heads.The cam from the Fleetwood should make a good match for the heads, my research on it shows it was designed for a heavy car in the lower rpm range which is probably well suited for my application.As far as the intake goes what would you recommend a dual plane or a single to make tunning easier with the TBI, or would it make any difference? I have heard a dual plane intake works best at lower rpm's. This is not my every day driver so fuel milage is not a big issue I am just looking for lots of torque and a somewhat smooth idle it will not see much high rpm use.

 

By the way RFmaster and Fast355, Thanks for taking time to discuss this topic I will save this information and apply it to my build you guys have given me a lot of good info.I will post my progress as I go. This is a long term project as I am on a budget, you know a part here a part there but it will come together, hopefully sooner than later.

 

Since your engine is for a DD which has to operate over a wide range of conditions I would revert to a dual plane fully heated intake (non-air gap) design. With this intake the base tune will be relatively stable over seasons, although some top end performance might be diminished. From driver perspective, in DD, you'll never know the difference. Good luck with project! Sounds like you are doing all the right things. Oh yea, the fleetwood cam should be OK - that was one large barge from a caddy!

//RF

 

The L30/L31 and B-car L99/LT1 cam are IDENTICAL in the engines I have pulled apart. Both had the 779 stamped in the end of them.