I am swapping in a 350 with comp cam ~270 adv dur, around 9.5 CR and perhaps Edelbrock aluminum heads very soon. My T/A currently has a 305 HO (L69).

I can get a TPI from a 305 with everything (computer and harness) for cheap, but I am not sure if I should go from carb to TPI. I have few questions for you TPI fans .

1) Can TPI support the hp level of my 350 (with or without modification)?
2) Will I get much better mileage?
3) Is it a difficult swap (I know carbs but donīt know anything about TPI)?
4) I have heard that TPI canīt breath over 4500-5000, is it true (usually I donīt go over 5000 rpm so perhaps that is not a problem).
5) Is there anything special I should think of when I am considering this swap (recomendations, problems etc)?
6) If I would change to 383 or 400, would TPI still work for me?
7) I is worth it?

Thanks in advange

Nonni

 

nonni,
ill try and take a stab at this...
first this cam.. duration @ .050" and lobe seperation angle
generally tpi can be had from $50-600 with some extra things to buy.
<b>1) Can TPI support the hp level of my 350 (with or without modification)?</b>
to be honest probably but understand a TPI is a torque application
engine. meaning the power output is between off idle to 5200.
<b>2) Will I get much better mileage?</b>
probably but like carbs itll need to be tuned. and since your in Iceland
youll probably be the one to do it.
<b>3) Is it a difficult swap (I know carbs but donīt know anything about TPI)?</b>
its a manifold swap, fuel pump change, and wiring challenge.
<b>4) I have heard that TPI canīt breath over 4500-5000, is it true (usually I donīt go over 5000 rpm so perhaps that is not a problem). </b>
in stock trim 4800-5200 is usually best. with modifications to
intake ports, runner profiles, and throttle bodies more can be
achived. but with that also heads, cam and compression are crutial.
if you can provide the labor, have a general knowledge of engines
asemblies and repair, you can probably do the swap. troubleshooting
maybe a little hard if you dont have someone close to compare or
show what goes where.
there are many on this board that have done it, some regret it, some
praise it highly. just depends on the time and devotion youd want to apply.
airdeano
5) Is there anything special I should think of when I am considering this swap (recomendations, problems etc)?
6) If I would change to 383 or 400, would TPI still work for me?
7) I is worth it?

 

nonni,
ill try and take a stab at this...
first this cam.. duration @ .050" and lobe seperation angle
generally tpi can be had from $50-600 with some extra things to buy.
<b>1) Can TPI support the hp level of my 350 (with or without modification)?</b>
to be honest probably but understand a TPI is a torque application
engine. meaning the power output is between off idle to 5200.
<b>2) Will I get much better mileage?</b>
probably but like carbs itll need to be tuned. and since your in Iceland
youll probably be the one to do it.
<b>3) Is it a difficult swap (I know carbs but donīt know anything about TPI)?</b>
its a manifold swap, fuel pump change, and wiring challenge.
<b>4) I have heard that TPI canīt breath over 4500-5000, is it true (usually I donīt go over 5000 rpm so perhaps that is not a problem). </b>
in stock trim 4800-5200 is usually best. with modifications to
intake ports, runner profiles, and throttle bodies more can be
achived. but with that also heads, cam and compression are crutial.
<b>5) Is there anything special I should think of when I am considering this swap (recomendations, problems etc)?</b>
if it is a stock TPi youll be ok with it, but youll want to modify the
airflow with gasket matching the manifold and cylinder heads,
port match the runners, massage the plenum. there are tech
articles on this on the forum.
<b>6) If I would change to 383 or 400, would TPI still work for me?</b>
could but it will more than likely be a super ram, or miniram manifold
for those appz.
<b>7) I is worth it?</b>
if you can provide the labor, have a general knowledge of engines
asemblies and repair, you can probably do the swap. troubleshooting
maybe a little hard if you dont have someone close to compare or
show what goes where.
there are many on this board that have done it, some regret it, some
praise it highly. just depends on the time and devotion youd want to apply.
airdeano

 

Thank you for your help airdeano, your explaination was very helpfull

I donīt know a lot about TPI (I am sure you figured that out allready) but I am willing to learn. I am sure I will have to learn sometimes and I think this time is as good as any. As you mentioned I canīt get much help localy (I have only heard of one TPI swap in Iceland) so I have to learn everything about it (should find something on Amazon).

Now that I am starting to look into it a bit, I have few more questions (hope I am not starting to be a pain in the #$&! ).

As I mentioned before this TPI is from an 85 or 86 305 (the owner is not 100% sure), I would be using this thing on my 350, ~270 adv. dur,(lift around 0.45-0.47) with 9.5 CR. Perhaps I would use Edelbrock aluminum heads (wich I can get used) with 2.02/1.6.

I can get this TPI with all harness, ignition and fuel pump (with everything, ECM, sensors etc) for almost free (he is willing to take an old 327 as payment, I am sure I will neather sell or use that motor). Only downside is that one of the runners is damaged so I would have to change that (around $200 in Summit).

My questions are:

1) Could TPI from 305 support my 350 if I change the injectors to 22 lb given that I donīt rev it over 5000 rpm (the ignition would be comming of the 305)?
2) If not, is it possible to let this TPI support my engine (what to do)?
3) Will it be easier to use MAF system (85~89) than Speed density TPI (donīt have to burn chips)?
4) When you tune older type TPI I am sure you adjust the ingition, what else do you tune?
5) Is it possible to take a wild guess how many horsepower and how much torque this engine would be making (if I should use those edelbrock aluminum heads).
6) Do you know of any good site about this swap.

Thanks in advange

Jon H. Gudjonsson

Other information about my T/A is,

1986 Transam, L69 (with roller) with Holley 600, Torker II, non computer Hei, MSD6AL, MSD superconducter 8.5 mm, MSD coil, headers (short), NO Cat (donīt have to in Iceland), 2.5 single exhaust, Flowmaster 80, TH700R4, ~2.77 with posi.

My new engine is almost ready, it is 350, 4 bolt, older than 1980, flattop pistons. I have to choose heads and if I should use carb or TPI, currently it has Holley Street Dominator manifold, smoke heads, comp cam (non roller) around 270 adv. dur with lift around 0.45-0.47 (my brother gave me this engine, he is not sure about the cam and I have not checked yet). This engine is has been started once (and broken in) and the sound was sweet .

 

1) Could TPI from 305 support my 350 if I change the injectors to 22 lb given that I donīt rev it over 5000 rpm (the ignition would be comming of the 305)?
2) If not, is it possible to let this TPI support my engine (what to do)?
3) Will it be easier to use MAF system (85~89) than Speed density TPI (donīt have to burn chips)?
4) When you tune older type TPI I am sure you adjust the ingition, what else do you tune?
5) Is it possible to take a wild guess how many horsepower and how much torque this engine would be making (if I should use those edelbrock aluminum heads).
6) Do you know of any good site about this swap.

1) Yes, because the TPI systems are identical except the injectors.

2) N/A

3) You will have to make a chip with either one if you go radical with the engine combination. A SD TPI system however will be a lot easier to tune then a MAF systerm. I'd go with SD.

4) Settting "base timing" is pretty easy. You disconnect the "set timing" connector and set the distributor between 6-10 degrees with the use of a timing light. To REALLY be able to tune it you'll need chip burning software and equipment. This way you can alter the ignition curve, how much advance at what RPM, how much fuel at what RPM and what load level, etc etc A MUCH better way to tune it.

5) 270 adv duration sounds... small. I would go with an Edelbrock RPM cam if you're gonna use their Edelbrock RPM heads. I would still go with that cam even if you use the regular Performers. The duration is in the ballpark of 230/240 and close .500 lifts which is very decent. This combo made 420 HP on Edelbrock's dyno. With a TPI AND a custom chip I say you should make around 360-370. That's very optimistic though. Why not STAY carbed... and make 420 ? You'd be running mid to high 12s easily ! That would make one wicked thirdgen... for pretty cheap.

 

Thank you for your answears Blackened,

Allmost everybody I have talked to have recomended to stay awai from TPI. I was mostly considering TPI because I use my T/A daily over the period from April - december. I have also heard that when TPI is tuned I donīt have to worry about it, it stays tuned (it is not alwais fun to have Holley carb). I also thought it might be a good challange

When my carb is hot and I stop for ~5-10 minutes and then start it again, then my engine starts to hesitate when I take of.

I think it is an 85 TPI (it is really hard to find TPI in ICELAND) and I have heard the ECM from 85 is no good (I am I right?). My uncle has offerded me a Holley injection for some more money but I think that is an TBI system. So I think I will just have to stay carburated.

Nonni

 

Actually the mas air system is more lenient when it comes to tunning with is a good thing in your case but it has limitations as for SD it doesn’t have the limitations and the sky is the limits when it comes to them but every time you change something on your car get ready for a chip change with SD systems usaly for smaller mods exhaust things like that the mas system will not require a new chip to be burned as far as what witch is better well every one has their own opinions on this I run the hot cam with 1.6 roller rockers on it it has 525 lift and I use the mas air system it runs good but could be better with some more tuning I’m thinking of changing to a DFI system myself and posibly getting an ATI turbo charger. I think that system would be fine for you if you can go to a 22lb injector make your own adjustable fuel pressure regulator and use a ECU out of a 87 or newer car and run a chip out of an 89 this is your best bet. You will probably want to learn how to burn your own chips you can do it your self for the same price as to buy a chip check out the tech articles there is plenty their on this. I have an extra ECU that you can have cheap but I don’t know what it would coast to ship it to you from the US I also have a set of stock 22lb injectors if you cant find them over their. You should defiantly port match every thing and port the plenum If you decide to do it let me know Ill be glad to send you as meny pics as you need of this. As for the runners I would go a head and get the slp runners from summit and port match the plennum to them. Don’t let tpi intimidate you it is aculy a easy system to work with and once you have it running write you don’t have to mess with it any more.After having it on my car I would never go back to a carb I even have a 68 fire bird that Im putting tpi on.

 

Those pictures would be appreciated, if those are not very big you could send them to my Hotmail account, nonni1972@hotmail.com. If they are HUGHE you might have to send them to my work address.

Is this ECU from an 87 TPI? It is almost sertan I canīt get 22 lb injectors in Iceland (would have to order them from USA). How much was you thinking about for the ECU and the injectors?

Do you know how much a chip from an 89 would cost in USA? Is it better than buy a custom chip?

I did some reading on the Best Damn Garage on the Net and on the tech section on this side, do you know of some other good sites?

Thanks,

Nonni

 

hey man if u are lookin for a set it and go intake system then tbi is it. the only adjustment is the idle. just sumtin to think about

 

My car donīt have a smoke pump or Chaircoal canister, do I have to use that with TPI?

I have noticed that Edelbrock advertises Edelbrock RPM and other heads wich are smoke legal. Does TPI care what heads I use?

Do I have to get other headers if I have TPI than they simple ones I use with my carb setup?

Nonni

P.s. Most people tell me to stay awai from TBI, so I will not swap out my carb for TBI.

P.p.s. My car is that old I donīt have to pass a stright emision test, the only thing they measure is % of CO. I donīt even have to have a Cat. Those are the regulations in Iceland.

 

Sorry I didnt get back with you my phone was dead so this is the firts time iv had a chance to get on line. I had changed my e-mail to earl87gta@yahoo.com I will e-mail you off the board .