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Listen and Learn
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Discussion Starter · #1 ·
Okay... I have a friend that wants me to rebuild the motor out of his 86 f-body. Its a 305 TPI with an automatic transmission. He was having issues with it over heating and drove it anyways and now the engine runs pretty rough...

Im thinking instead of rebuilding the 305 why not swap in a rebuilt 350... stock rotating assembly just new rings and bearings maybe a small cam and try to find a set of those 305HO 416 heads and rebuild those for him. Of course I will need to burn a new chip for the ecu and add some larger injectors..

What would you guys do if you had a 305 that needed rebuilding. My vote is swap a 350 into its place. His budget is between 1000-1200 and I think I can make it work once I get the quote back from the machine shop.
 

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Discussion Starter · #3 ·
123pugsy said:
I'd go 350 but not sure about the small heads.
I have heard quite a few good things about these heads with some minimal port work done to them... plus with the tpi intake this is gonna be built for low end torque, those intakes aren't really known for their high rpm breathing abilities.
 

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Rod...from a Chrysler?
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TPI is no good after 4800 rpm's but I found restrictions can really choke it off.

Intake and exhaust on my truck TPI were restricted and robbing a bunch of torque and HP.

Just seems smaller valves would do the same.

Second entry down shows the difference in dyno pulls after removing restrictions. Maybe these heads are a totally different deal, but in theory restrictions cost torque and HP.

TPI DYNO PULLS
 

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personally i would find a complete vortec 350, inspect it, and then change it to a carb set up, ditch the ECU. he should have a 700R4 trans which can easily be adapted to a carb set up with the detent (TV) cable.
 

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Discussion Starter · #6 ·
my87Z said:
personally i would find a complete vortec 350, inspect it, and then change it to a carb set up, ditch the ECU. he should have a 700R4 trans which can easily be adapted to a carb set up with the detent (TV) cable.
This will definitely be a consideration but I think he wanted to keep it efi.
 

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Discussion Starter · #7 ·
123pugsy said:
TPI is no good after 4800 rpm's but I found restrictions can really choke it off.

Intake and exhaust on my truck TPI were restricted and robbing a bunch of torque and HP.

Just seems smaller valves would do the same.

Second entry down shows the difference in dyno pulls after removing restrictions. Maybe these heads are a totally different deal, but in theory restrictions cost torque and HP.

TPI DYNO PULLS
I think the posts I have seen on these heads involved installing 1.94" intake valves
 

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Footbraker
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You won't necessarily even have to change the ECU/Prom or injectors. I swapped in a 350 (crate motor for an 87 pickup) into my 87 IROC back in 1991. This was a MAF setup not speed density and all I did was use an adjustable fuel pressure regulator to bump up the pressure to 50 psi. Only other mods were edelbrock headers, 3" single exhaust, and a homemade ram air setup.
It worked flawlessly until I swapped cams. IIRC the new cam was a Blue Racer dual pattern with 112 lsa, 204/214 duration and .435/.465 lift. After the cam swap the car would surge a bit at idle and sometimes stall sitting at lights. Had a custom PROM burned at Arizona Speed and Marine which cured the idle problem but made the mpg nosedive and made no improvement in ET/mph at the strip.
I would think with the right cam and an adjustable regulator on a mass air motor you could do the swap without new injectors or a prom.
 

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If he wants to invest some money into it and youre going to try your hand at burning, you might want to see how he feels about picking up a different manifold and heads. Over on thirdgen.org, you can always find someone doing a LS1 swap, and there usually a few minirams, ported OEM intakes, worked iron heads, 58cc aluminum heads etc on the for sale boards. Also, there are some racing circles that need date coded 305 blocks, so it should be worth more than scrap.
 

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Discussion Starter · #15 · (Edited)
AutoGear said:
If he wants to invest some money into it and youre going to try your hand at burning, you might want to see how he feels about picking up a different manifold and heads. Over on thirdgen.org, you can always find someone doing a LS1 swap, and there usually a few minirams, ported OEM intakes, worked iron heads, 58cc aluminum heads etc on the for sale boards. Also, there are some racing circles that need date coded 305 blocks, so it should be worth more than scrap.
awesome thanks for that advice. Ill definitely take a look. I just figured with the way I wanted to build the engine his transmission and rearend should last longer lol.
 

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I have an 87 TA WS6 that the girlfriend putters around in; I figure I would replace the injectors, and rebuild the heads. If I was feeling enterprising, I'd get some 58cc aluminum heads from a vette, however the EGR setup is different on the Vette setup, so you may need the Vette intake with the heads
For a cam (I have the roller cam block) Id use a TPI 350 cam., perhaps a GM 'Hotcam' from the LT motors. If you use this cam, you have to adjust the height of he dowel pin at the front of the cam. I like the 'Pizza Box' Super Ram manifold because it has more midrange than the Short Ram and etc. The other option would be the FIRST TPI setup; which is better than the ported OEM upper with the oversized runners. It looks very similar to the factory induction (which I kind of like). You may be able to find used. This manifold is best on 350+cid though.

The TPI manifold was designed for the 305 to begin with and used on the 350 as well, it should flow enough for what hes doing.

Its fairly obvious but make sure if you decide to swap in a 350 you get everything you need for MAF or SD sensors, which ever way you decide to go.

I don't really see the carb thing as a plus if he only wants a driver out of it.
Theres some guys on the TGO boards pushing a lot of power through TPI's.

Another option if you're swapping motors would be an LT1; the swap is easier than an LS motor and they make plenty of power stock.
 

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If you do get into this would you mind posting some pics of the engine wiring before it comes out? I hav e an 84 Z28 that I'm putting a TPI 350 in and I'm stuck on some of the connectors and can't seem to find anyone locally with a TPI F-body. Thanks in advance. You can probably find some cool stuff for the project at www.hawksthirdgenparts.com they have taken care of me for quite a few things.
 

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Discussion Starter · #19 ·
Regular6d said:
If you do get into this would you mind posting some pics of the engine wiring before it comes out? I hav e an 84 Z28 that I'm putting a TPI 350 in and I'm stuck on some of the connectors and can't seem to find anyone locally with a TPI F-body. Thanks in advance. You can probably find some cool stuff for the project at www.hawksthirdgenparts.com they have taken care of me for quite a few things.
Yeah if I remember ill snag some pics. I found some wiring diagrams and wire layouts online somewhere. If I remember where ill also post those links.
 

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Discussion Starter · #20 ·
Well lucky me I show up and he already did me the favor by pulling the top end of the motor apart.... ugh this is gonna be a night mare to put back together now. There is a coffee can of bolts instead of bagging everything individually. Good none of this AIR emissions crap is going back on but still... AAAAHHHHHH!!!! Any suggestions on what you guys would do heads and cam wise. The car did have the 416 heads with it so as long as they arent cracked I wouldn't mind playing around with getting some 1.94or 1.90 x 1.50 or 1.60 valves put into them and doing the accompanying port work to them.
 
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