My 305 TPI swap thread

Mr_Roboto · Post by **Mr_Roboto** » Tue Sep 19, 2006 5:43 pm

I figured this forum was getting pretty lonely without a swap thread, so I figure I'd start one although I'm still not anywhere near ready to install. Keep in mind that this setups gonna be ghetto because of my current fiscal sitiuation in college. Here's what I have
-1986 TPI engine (non roller 1 piece rear main) W/125K on the clock
-ported TPI with Mr. Gasket big intake runner gaskets.
(146 is the PN I believe, I got it from Auto Zone)
-30#/hr injectors from a Grand National.
-ported 416 TPI heads.
-headman 68600 headers.
-ebay mounts.

Engine management is going to be Megasquirt EFI, I already have the new fuel pump installed.

This weeks work consisted of:lapping the valves, cleaning the heads at a car wash and applying a couple coats of high heat engine paint from them. I also have the head decks cleaned up. My next purchases and work will be getting gaskets for the heads to put them on and valve springs. I'm using the stock cams but GM springs are known to lose pressure badly from the factory so I figure it's way easier to do while the heads are off.

BLAZER · Post by **BLAZER** » Wed Sep 20, 2006 2:25 am

Check out some "Z28" springs from competition products. Very cheap, $30 or so, and great quality, take up to almost .500 lift and perfect for a stock cam up to a mild/med performance cam.

Mr_Roboto · Post by **Mr_Roboto** » Fri Sep 22, 2006 10:54 am

BLAZER wrote:Check out some "Z28" springs from competition products. Very cheap, $30 or so, and great quality, take up to almost .500 lift and perfect for a stock cam up to a mild/med performance cam.

Thanks, that was the name I was looking for. I'd done a search on thirdgen.org and couldn't find it. Got em ordered today, so hopefully they'll be here in time for next weekened to get these heads together.

Mr_Roboto · Post by **Mr_Roboto** » Sat Sep 23, 2006 8:37 pm

All right, quick question on accessories; I'm using V-belts for this setup, as I have everything for it, I'm using old style heads and it'll simplify install not to mention let me ditch the "horse shoe." Now my question; I've got an old power steering pump off of a 350 motor, does anyone know if the newer ones are metric fittings? I'm not sure if/when GM did this, but If they did I'll have to yank the pulley off my current one or a spare and then swap the V-belt pulley on. My other question is, will a hydraulic shop be able to make the fuel lines to extend the TPI stuff, or can I use regular flare fittings and buy adapters for the lines?

Mr_Roboto · Post by **Mr_Roboto** » Wed Sep 27, 2006 11:00 am

small update, but hey I'm getting somewhere. First off, I got the remainder of the set of positive valve seals for the heads, so none of them have the "umbrella" seals like they used to. Had a set for the 4.3L which are the same, just needed a couple extra to round the set off. Hopefully I'll no longer get the chevy "puff" on startup. Waiting on the springs from competition products then I'll be able to finish building my heads!
I also worked on my headers some this sunday. Since there have been issues with the 68600s before I decided it wasn't worth it to take chances. Firstly, I cut the bars that join the middle ports to the outer ones on my flanges. After that I took a file and flattened the mating surface of the port. I'm going to use anti-siezed bolts/studs with these, and copper RTV on the ports. Another thing is that I will be making bolt retainers like the OEM setups had, this way the bolts won't come out near as easliy. I hope between all these precautions I'll end up with a leak free setup. I thought the 68600s had 2.5 inch pipe as the reducer outlet diameter, the reducers that came with mine are about 2.25 diameter. Is this right, or am I just nuts?

Mr_Roboto · Post by **Mr_Roboto** » Fri Sep 29, 2006 3:11 pm

Well, I was going by the scrap yard to cash in my aluminum, and I was pouring out my steel when low and behold I saw a muffler from a diesel truck. For the grand total of $1.36 after tax I got a 3 inch in/out round aluminized muffler and 2 3 inch mandrel bends. I can't wait to get this thing on!

lockdoc · Post by **lockdoc** » Fri Sep 29, 2006 3:24 pm

I wouldn't trust copper RTV to seal anything to do with the exhuast. It's sure to burn right off. At the least use stock exhuast gaskets seeing that hand filing will not match a machined surface. The flange on the 68600's is 3". I used 2 1\4" reducers on mine. And again, I will state that I have never had my 68600's leak at the manifold to date with copper gaskets.. Though I do seem to have a recurring problem blowing out the pass side aluminum flange gasket which I think is due to the exhuast pipe not fitting squarely.

canadavan · Post by **canadavan** » Fri Sep 29, 2006 5:13 pm

I've been running copper gaskets with my 68600's and no leaks. Bolts haven't even loosened.

Mr_Roboto · Post by **Mr_Roboto** » Fri Sep 29, 2006 7:56 pm

Time for some pics, just got access to a camera tonight.

This was the muffler I picked up, not too bad for the cost eh?

Looks even better going through IMO, I bet this thing will support decent power. Wonder how it sounds.

Here's my headers that I've worked over some, notice the lack of bars in between the ports.

Just a quick pic of my clean up job on the center ports, nothing special just a file. The lip on the edge of the port was sticking up enough where I could feel it. not a good thing.

My head with paint and a painted valve cover. Doubt that the paint will last long but at least it was on there when I put the motor in.

Another pic, showing off the new valve springs. Ain't they purdy?

ed to fix broken images.

peter · Post by **peter** » Sat Sep 30, 2006 4:03 am

Can't beat the beauty of GM orange, can you?

I think you've got a good idea there, removing the metal between the exhaust ports. Removing the bead around the ports on the headers may be a better idea as well, I just don't understand why the manufacturers would put the bead there to begin with. I'd personally be more comfortable having the header flanges surface-ground, but that'd prolly cost more than new headers to begin with.
Lookin' good so far, Robo

SafariRob · Post by **SafariRob** » Sat Sep 30, 2006 5:28 am

Robo, looks to me like those headers will work out for you. I started with the 68600s and never could get them to stop leaking at the heads--finally replaced them with exhaust manifolds from a 350 and that was the end of the leakage problems.
I also don't understand why Hedman uses the welded bead around the ports on the flange, but I've seen where Hooker does it, too. In both cases the bead looked to be hastily and sloppily ground with a hand grinder.

Mr_Roboto · Post by **Mr_Roboto** » Sat Sep 30, 2006 6:23 pm

Got head bolts and gaskets offa ebay, 170,000 PSI head bolts and a set of "open box" Felpros from Northern Auto Parts. After I get those I should be ready to rock!

Astro95 · Post by **Astro95** » Sun Oct 01, 2006 8:03 pm

On some of the cheaper brands of headers, the weld is only done on the inside of the flange. If you grind that down flush with the flange, they might develop leaks between the flange and the primary pipes.

Mr_Roboto · Post by **Mr_Roboto** » Sun Feb 25, 2007 9:45 am

All right, some major updates since I've been neglecting this page.
Got what amounts to pretty much the balance of my exhaust parts, I may need some 3 inch tubing but that should be about it besides clamps if my buddy doesn't MIG it for me.

The mandrel bends were $30 shipped from Vossracing, and the Y-pipe was $35 from the local store and is made by Magnaflow. It looks well constructed as well, even though the design isn't exactly "traditional" IMO. The bends are 2.25, the Y-pipe is 2.5 into 3 inch, I couldn't get 2.25 into 3 inch so I had to use the reducers that were $3 each from the local parts store.

Since the last reply on my thread, the Megasquirt has been repaired, I'd done some serious damage to it by setting it for high impedance injectors and running low impedance ones. After I let the smoke out it was quite a bit of work to repair, having to replace some of the power supply circuit and almost all of the injector driver circuit. This is the TPI injector harness I built. If I had to do it again, I would have set these up to where when the injectors fired it would fire2 injectors on each side at a time versus 4 injectors on one side to reduce the potential for pressure drop.

This is a Walbro 307M fuel pump I picked up with low miles from a parts car on a buick board. These put out 255LPH at a base pressure of 43 PSI, and supposedly supports ~550hp in a boosted environment. These pumps also use a Gerator type pump rather then a vane type which is common in OEM stuff. The strainers for these are a PITA to get without a pump kit since the nose is larger then a stock style one, thanks to fullthrottlespeed.com for hooking me up. This has been in the tank months now, but just got about to posting it.

Parts for this weekend. They include an O2 sensor for tuning it when I get it re started, a bung to put in the oil pan for the turbocharger, a Summit K1102 camshaft and lifter kit, ARP oil pump stud I have lying around, and gaskets to put it back together. The pan gasket is a high buck neoprene one so I don't need to worry about replacing it.

Had some help at the shop today, this is my buddy Nick installing bolts into the old cam to yank it out.

Here he is inspecting the old cam, it's in good shape but SMALL. Thank goodness we know how to fix that.

Where power robbing smog junk belongs.

Me applying moly assembly lube to the cam, this stuff barely comes out of the bottle. I didn't apply a gallon like they do on TV and the magazines, apparently a whole bottle for one cam isn't essential.

Me spreading it out. This stuff is majorly sticky, and strings out for a foot. Really nasty to work with.

Me installing the cam. Just took my time, it seemed to go well. We'll find out soon.

I went out and blew $20 on a timing set. The original was in there, and I've heard GM nylon timing gears are a time bomb. There was also a ton of stretch in the chain, this engine supposedly had 125,000 on it and I'd believe it with the shape the chain was in.

Got the timing cover and intake on to keep squirrels and such from building a nest in it before I get to it again. More to come, when I get time.

Mr_Roboto · Post by **Mr_Roboto** » Sun Feb 25, 2007 10:12 am

Whoops, forgot a few pics. This is my oil pan, I put the drain for the turbocharger to come in it since it's off and easy to do.

Hole drilled, I cleaned it up so the RTV would have a chance of sealing when I put it on.

The pipe nipple I used is sticking out too much, probalby get hit by a crank weight. Have to clearance it some.

After a tad of work with the grinder. Much better.

Chevy & GMC Vans

Chevy & GMC Vans

My 305 TPI swap thread

My 305 TPI swap thread