305 TPI to 350 or 400 swap
03-30-2009, 12:23 PM
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305 TPI to 350 or 400 swap
Hey guys, just joined the forum.
Brought home my new 86 Iroc Z project Saturday and have some questions about TPI setups and what all is required to upgrade to the larger 350 or 400 cubic inch engines?
The factory 305 engine had too much of the tall skinny pedal and now has some lower end noise.
I got a fresh built 350 4 bolt main long block with 64cc Chamber 300 hp Goodwrench crate heads with center bolt valve covers thrown in with the car. Not sure on piston size. Could be stock, might be 30 over. Not sure on the camshaft either.
I also have a built 400 sbc as an option for this car, but it was built for pretty much Drag Strip only using the following:
12:1 100cc dome pistons, standard 4.125" bore, Chevy 350 Rods/arp rod bolts, 76 cc chamber heads, rebuilt with big valves, heavy springs, roller tip steel rockers, hardened pushrods, Perfect circle plasma moly rings, Clevite 77 rod/main bearings, melling high volume oil pump, Air Gap Alum. dual plane intake, Holley 750 dbl. pumper dual line carb, B&M 2500 stall converter and built Turbo 350 auto tranny.
Summit K1107 cam-Advertised Duration 292/302, Lift .488/.510 114 deg. lobe separation 3,000 to 6,500 rpm operating range
I am wanting to keep the TPI setup on which ever engine I go with to run in my Iroc. Just wondering which motor would work best with the TPI setup or if I should go with carb setup instead of the TPI?
I want to keep this car streetable, but still be able to spank those young cocky guys with their 302 Mustangs running around everywhere...
I have no past knowledge with TPI setups, so this is all new to me, and I am working with a limited budget due to having two teenagers, one still in high school and one in College and a wife that only wants to work part time and doesnt support or appreciate my hobbies...
Any help or suggestions are greatly appreciated since this is the start of my build. I dont want to screw it up, or create a lost cause project.
Jim C.
Brought home my new 86 Iroc Z project Saturday and have some questions about TPI setups and what all is required to upgrade to the larger 350 or 400 cubic inch engines?
The factory 305 engine had too much of the tall skinny pedal and now has some lower end noise.
I got a fresh built 350 4 bolt main long block with 64cc Chamber 300 hp Goodwrench crate heads with center bolt valve covers thrown in with the car. Not sure on piston size. Could be stock, might be 30 over. Not sure on the camshaft either.
I also have a built 400 sbc as an option for this car, but it was built for pretty much Drag Strip only using the following:
12:1 100cc dome pistons, standard 4.125" bore, Chevy 350 Rods/arp rod bolts, 76 cc chamber heads, rebuilt with big valves, heavy springs, roller tip steel rockers, hardened pushrods, Perfect circle plasma moly rings, Clevite 77 rod/main bearings, melling high volume oil pump, Air Gap Alum. dual plane intake, Holley 750 dbl. pumper dual line carb, B&M 2500 stall converter and built Turbo 350 auto tranny.
Summit K1107 cam-Advertised Duration 292/302, Lift .488/.510 114 deg. lobe separation 3,000 to 6,500 rpm operating range
I am wanting to keep the TPI setup on which ever engine I go with to run in my Iroc. Just wondering which motor would work best with the TPI setup or if I should go with carb setup instead of the TPI?
I want to keep this car streetable, but still be able to spank those young cocky guys with their 302 Mustangs running around everywhere...
I have no past knowledge with TPI setups, so this is all new to me, and I am working with a limited budget due to having two teenagers, one still in high school and one in College and a wife that only wants to work part time and doesnt support or appreciate my hobbies...
Any help or suggestions are greatly appreciated since this is the start of my build. I dont want to screw it up, or create a lost cause project.
Jim C.
03-30-2009, 01:54 PM
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Welcome aboard thirdgen.org.
First, understand TPI was a marketing tool more than a performance system. Gave great seat-of-the-pants acceleration, decent gas mileage, and was pretty much maxed out by the factory. You want more, start changing hardware.
When you're talking about a healthy larger displacement engine, the best thing to do with TPI is change out the base, runners, and plenum, and the best bang-for-buck there is the Holley/Weiand Stealth Ram. It can handle either of those engines without breaking a sweat.
After that, it's details. The 400 is probably built a little too radical for TPI, but with careful parts selection and good tuning, it will still be okay. The compression is a bit on the high side, though.
The 350 would probably be fine as well, depending upon what heads and cam it actually has.
First, understand TPI was a marketing tool more than a performance system. Gave great seat-of-the-pants acceleration, decent gas mileage, and was pretty much maxed out by the factory. You want more, start changing hardware.
When you're talking about a healthy larger displacement engine, the best thing to do with TPI is change out the base, runners, and plenum, and the best bang-for-buck there is the Holley/Weiand Stealth Ram. It can handle either of those engines without breaking a sweat.
After that, it's details. The 400 is probably built a little too radical for TPI, but with careful parts selection and good tuning, it will still be okay. The compression is a bit on the high side, though.
The 350 would probably be fine as well, depending upon what heads and cam it actually has.
03-30-2009, 03:06 PM
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Re: 305 TPI to 350 or 400 swap
Thanks for the welcome. I will try to go into a little more detail on my project. I tend to be long winded sometimes so please excuse that.
Guess my biggest decision is to keep the car TPI, or go with Carb.
GM Carb/HEI setups are more within my knowledge base and experience. It sounds to me like tuning in the TPI setup to get more HP than stock would basically take away the fuel economy benefit and I could keep the quick launch aspect by just running a stall converter without the TPI.
Not to mention be much more costly on the Electronic upgrades and hardware upgrades.
My 350 engine is basically a builder engine. Nothing on it is set in stone. I can pretty much do whatever I want with it right now. Cam can be changed. I have no idea what size the existing cam is anyways so it is probably going to be replaced with new anyways.
Heads on it are cast iron 64cc chamber. Casting #s say they are from a GM Crate engine rated at 285/300 hp. Without pulling them off the engine, I dont have any more info. on them. I am planning on pulling them though because I have to know what pistons are in the engine also.
Basically, I can start from scratch on this 350 4 bolt main setup and would like to build it like it needs to be built to get me around 350HP-400HP to the rear wheels and still be dependable to cruise to use as a DD upon occasion and cruise to the coast on vacations and trips. Wondering also if the 700R4 auto trannys can take the HP as well as the Turbo 350's. I have been led to believe that the 700R4 trannys are much more expensive to have built to take the higher HP engines than the Turbo 350's, but that overdrive gear sure is nice on trips.
The 400 engine is a little more set in stone in some of its buildup already.
I think the 400 engine is pushing about 10.5:1 compression in its current form even with the larger 76cc chamber heads. I opted for this head selection for basically two reasons on this engine. First was to hopefully keep my compression ratio down low enough to run 93 octane pump gas. The second was because it already had the 2.02/1.6 Stainless valves and 3 angle valve job, and the rocker studs pinned for the larger lift camshaft.
The 400 engine has 20 min. run time on break in. Was carrying 80 psi. oil pressure at about 2000 RPM's during initial break in run. This motor/Turbo 350/2500 rpm stall was built for a 86 Toyota truck to run 4.38 gears through the 1/8 mile. I am just not sure how well suited it would be for a Cruiser car. Camshafts are easy to replace, so I could easily choose a better profile cam for this Iroc project.
The Iroc already has 2.5 or 3.0" lead pipes coming into one 4" pipe back to a Hooker dual outlet high flow muffler and 2.5" pipes.
Also has Edelbrock headers.
No Cat. System at this time. Not really planning on running them either due to extra costs of adding them back. Right now I live in a non-inspection state where this is not required.
Guess my biggest decision is to keep the car TPI, or go with Carb.
GM Carb/HEI setups are more within my knowledge base and experience. It sounds to me like tuning in the TPI setup to get more HP than stock would basically take away the fuel economy benefit and I could keep the quick launch aspect by just running a stall converter without the TPI.
Not to mention be much more costly on the Electronic upgrades and hardware upgrades.
My 350 engine is basically a builder engine. Nothing on it is set in stone. I can pretty much do whatever I want with it right now. Cam can be changed. I have no idea what size the existing cam is anyways so it is probably going to be replaced with new anyways.
Heads on it are cast iron 64cc chamber. Casting #s say they are from a GM Crate engine rated at 285/300 hp. Without pulling them off the engine, I dont have any more info. on them. I am planning on pulling them though because I have to know what pistons are in the engine also.
Basically, I can start from scratch on this 350 4 bolt main setup and would like to build it like it needs to be built to get me around 350HP-400HP to the rear wheels and still be dependable to cruise to use as a DD upon occasion and cruise to the coast on vacations and trips. Wondering also if the 700R4 auto trannys can take the HP as well as the Turbo 350's. I have been led to believe that the 700R4 trannys are much more expensive to have built to take the higher HP engines than the Turbo 350's, but that overdrive gear sure is nice on trips.
The 400 engine is a little more set in stone in some of its buildup already.
I think the 400 engine is pushing about 10.5:1 compression in its current form even with the larger 76cc chamber heads. I opted for this head selection for basically two reasons on this engine. First was to hopefully keep my compression ratio down low enough to run 93 octane pump gas. The second was because it already had the 2.02/1.6 Stainless valves and 3 angle valve job, and the rocker studs pinned for the larger lift camshaft.
The 400 engine has 20 min. run time on break in. Was carrying 80 psi. oil pressure at about 2000 RPM's during initial break in run. This motor/Turbo 350/2500 rpm stall was built for a 86 Toyota truck to run 4.38 gears through the 1/8 mile. I am just not sure how well suited it would be for a Cruiser car. Camshafts are easy to replace, so I could easily choose a better profile cam for this Iroc project.
The Iroc already has 2.5 or 3.0" lead pipes coming into one 4" pipe back to a Hooker dual outlet high flow muffler and 2.5" pipes.
Also has Edelbrock headers.
No Cat. System at this time. Not really planning on running them either due to extra costs of adding them back. Right now I live in a non-inspection state where this is not required.
Welcome aboard thirdgen.org.
First, understand TPI was a marketing tool more than a performance system. Gave great seat-of-the-pants acceleration, decent gas mileage, and was pretty much maxed out by the factory. You want more, start changing hardware.
When you're talking about a healthy larger displacement engine, the best thing to do with TPI is change out the base, runners, and plenum, and the best bang-for-buck there is the Holley/Weiand Stealth Ram. It can handle either of those engines without breaking a sweat.
After that, it's details. The 400 is probably built a little too radical for TPI, but with careful parts selection and good tuning, it will still be okay. The compression is a bit on the high side, though.
The 350 would probably be fine as well, depending upon what heads and cam it actually has.
First, understand TPI was a marketing tool more than a performance system. Gave great seat-of-the-pants acceleration, decent gas mileage, and was pretty much maxed out by the factory. You want more, start changing hardware.
When you're talking about a healthy larger displacement engine, the best thing to do with TPI is change out the base, runners, and plenum, and the best bang-for-buck there is the Holley/Weiand Stealth Ram. It can handle either of those engines without breaking a sweat.
After that, it's details. The 400 is probably built a little too radical for TPI, but with careful parts selection and good tuning, it will still be okay. The compression is a bit on the high side, though.
The 350 would probably be fine as well, depending upon what heads and cam it actually has.
03-30-2009, 06:26 PM
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Many members are getting both good HP and good MPG #'s out of their TPI set-ups. It will typically give you a better mix of HP & economy than carb will. Computer tuning is one of those unfounded fears that old school guys just have to get over.
03-30-2009, 10:28 PM
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Re: 305 TPI to 350 or 400 swap
I really dont fear ECU tuning, I have done multi port fuel injection swaps on Honda's and had to repin the harnesses and change out the ECU's. I just dont like the headaches and time consumed in doing it.
Carb's and HEI are much more simple to tune. No sensors, or ECU's, just a Carb and Timing light and you can pretty much bank on them.
What I do fear is that this TPI setup will not allow my 400 engine to achieve its full power potential, which is what I have decided to put into my Iroc. There is no substitute for cubic inches, so the sbc 400 will give me the most HP. Its also already built to handle more RPM's than the standard 400 since I have 350 rods and the shorter pin height dome top pistons.
Since this car will not be a daily driver, the fuel milage is not something I am going to worry about.
What all has to change besides going to the Weiand setup mentioned above to bolt a TPI setup onto my 400 engine that will deliver it enough fuel/air from 3,000 to 6,500 RPM's?
Larger Throttle body, injectors, ECU, higher volume fuel pump, air flow meter??? Sensors or mods to them???
Carb's and HEI are much more simple to tune. No sensors, or ECU's, just a Carb and Timing light and you can pretty much bank on them.
What I do fear is that this TPI setup will not allow my 400 engine to achieve its full power potential, which is what I have decided to put into my Iroc. There is no substitute for cubic inches, so the sbc 400 will give me the most HP. Its also already built to handle more RPM's than the standard 400 since I have 350 rods and the shorter pin height dome top pistons.
Since this car will not be a daily driver, the fuel milage is not something I am going to worry about.
What all has to change besides going to the Weiand setup mentioned above to bolt a TPI setup onto my 400 engine that will deliver it enough fuel/air from 3,000 to 6,500 RPM's?
Larger Throttle body, injectors, ECU, higher volume fuel pump, air flow meter??? Sensors or mods to them???
04-01-2009, 07:36 PM
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Re: 305 TPI to 350 or 400 swap
OK, after much deliberation and thought, I have decided on the 400 sbc and the Weiand/Holley Stealth Ram setup with LT1 52mm throttle body.
Now I guess my direction is set. Just do not know what else I will need to make my 400 setup run smooth in my Iroc. I already have Edelbrock headers, 2.5" lead pipes plumbed into single 4" cat back to Hooker performance muffler with 2.5" dual outlet tail pipes. I will not be running a Cat. so not sure what that will do to my 86 ECU/Distributor setup for the stock 305 TBI.
What I need to know is what would be:
1. my best cam/lifter setup
2. along with what injectors
3. and possibly what ECU changes to complete my build.
Any help/suggestions are greatly appreciated. I am working with a small budget on this project and would really like to do it right the first time.
I still want to keep my Iroc streetable, so my thoughts are to stick with the 700R4 tranny. Not sure if I even need a stall with this 400 and its torque?
Now I guess my direction is set. Just do not know what else I will need to make my 400 setup run smooth in my Iroc. I already have Edelbrock headers, 2.5" lead pipes plumbed into single 4" cat back to Hooker performance muffler with 2.5" dual outlet tail pipes. I will not be running a Cat. so not sure what that will do to my 86 ECU/Distributor setup for the stock 305 TBI.
What I need to know is what would be:
1. my best cam/lifter setup
2. along with what injectors
3. and possibly what ECU changes to complete my build.
Any help/suggestions are greatly appreciated. I am working with a small budget on this project and would really like to do it right the first time.
I still want to keep my Iroc streetable, so my thoughts are to stick with the 700R4 tranny. Not sure if I even need a stall with this 400 and its torque?
04-01-2009, 11:36 PM
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Higher stall will probably help.
There are some guys on the TPI forum that are converting it to be run off of the LS1 type PCM. Much better tunability, don't have to remove a chip and erase/reflash it, sequential injection, etc. More work to set up, but less to tune and certainly smoother with more power potential.
There are some guys on the TPI forum that are converting it to be run off of the LS1 type PCM. Much better tunability, don't have to remove a chip and erase/reflash it, sequential injection, etc. More work to set up, but less to tune and certainly smoother with more power potential.
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04-02-2009, 11:38 AM
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Re: 305 TPI to 350 or 400 swap
Thanks, I'll check out the TPI board and dig deeper.
Would I be better off keeping the 700R4 behind the 400, or would the Turbo 350 work better with my setup?
Also, I am thinking that the 700R4 uses a lockup converter, so I dont think my brand new 2500 stall in the Turbo 350 will work with the 700R4 will it?
Would I be better off keeping the 700R4 behind the 400, or would the Turbo 350 work better with my setup?
Also, I am thinking that the 700R4 uses a lockup converter, so I dont think my brand new 2500 stall in the Turbo 350 will work with the 700R4 will it?
04-02-2009, 12:06 PM
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
No, you need a TH700R-4 converter. It's actually a pretty decent transmission, but needs to be properly built to work well and last behind more power.
04-06-2009, 06:28 PM
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Re: 305 TPI to 350 or 400 swap
How strong is the body on my 86 Iroc T-Top car?
Due to low funds right now to get my car back on the road, I am having to consider just putting my 400 sbc in it right now with Holley Carb and HEI setup. I am also going to have to swap out the 700r4 with my built Turbo 350 and B&M 2500 stall.
Just wondering what all I need to look out for on the car if I get it to hook up?
Due to low funds right now to get my car back on the road, I am having to consider just putting my 400 sbc in it right now with Holley Carb and HEI setup. I am also going to have to swap out the 700r4 with my built Turbo 350 and B&M 2500 stall.
Just wondering what all I need to look out for on the car if I get it to hook up?
04-06-2009, 08:49 PM
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Subframe connectors should be considered a must. After that, you get into drivetrain parts weaknesses.
04-07-2009, 06:55 PM
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04-07-2009, 08:50 PM
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Car: 82 Berlinetta/57 Bel Air
Engine: LS1/LQ4
Transmission: 4L60E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
I recommend weld in, although I've never tried the bolt in type.
Brand - I've got Spohn in Berlinetta #1, am about to install UMI's in Berlinetta #2. I haven't really heard of anyone not liking any they've installed, but the Chassis forum might be a better place to research that.
Brand - I've got Spohn in Berlinetta #1, am about to install UMI's in Berlinetta #2. I haven't really heard of anyone not liking any they've installed, but the Chassis forum might be a better place to research that.
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