Progress Thread Komo's 1990 GT - Parts Gathering Purgatory & Home Remodel
- Thread starter gkomo
- Start date
I’m probably getting ahead of myself it’s most likely this
ty half broke ass engine causing the vibes.
With the pistons, things, and other stuff...
Maybe just pull it and do a stock rebuild?
I mean... if you pull the trans, you're 1/4 of the way there
Maybe just pull it and do a stock rebuild?
I mean... if you pull the trans, you're 1/4 of the way there
With a 'stock rebuild', is there anything i can do to make it more stout for the supercharger if i decide to up the boost down the road? From current 4-6lbs to 8-10lbs? I only want to do things once if i'm going down this path and will prioritize reliability over power.With the pistons, things, and other stuff...
Maybe just pull it and do a stock rebuild?
I mean... if you pull the trans, you're 1/4 of the way there
This car will probably never see over 400hp being out in California, but one day, a high 300's hp car would be fun.
Shortblock work is out of my scope of abilities so this is going to have to go to a shop.
I think a solid plan could be:
- rebuild the shortblock, keep it a 302 unless it needs to bored out to a 306. Keeping as much of my stock rotating assembly as possible. Add the TFS heads while this work is being done but keep the stock cam/intake
- new clutch/flywheel (or at least inspect clutch to see if it needs to be replaced. supposedly its new)
Engine parts i have on hand:
- P/N M6600D2 Ford Racing High Volume Oil Pump
- P/N ARP-154-4201 ARP Head Studs
- P/N 254-1804 ARP Oil Pan Bolts
- P/N 154-7904 ARP Oil Pump Driveshaft
- P/N 354-2103 ARP Intake Stud Kit
- TFS Twisted Wedge 170cc Heads
- Felpro one piece oil pan gasket
Engine parts i would need to buy for this endeavor (mostly copying from @nicholase build):
- P/N M-6253-A50 Ford Performance Spyder Plate & Dogbones Kit
- P/N M-6268-A302 Ford Motorsport SVO Timing Set
- P/N M-6500-R302H Ford Performance Lifters
- P/N 150-2501 ARP Balancer Bolt
- P/N 200-2802 ARP Flywheel Bolts
- P/N 250-1001 ARP Cam Thrust Plate Bolts
- P/N 245-1001 ARP Cam Sprocket Bolt
- P/N LRS-8501BHDW Front Cover Bolt Kit (WP & Timing Cover - ARP bolts)
- New waterpump of unknown brand at the moment
Parts to leave up to the engine builder/shop:
- Pushrods
- Gaskets
- Roller Rockers (1.6 or 1.7?)
- Misc stuff
- New shortblock parts like bearings/rings/etc.
You said you feel the vibration at 1500-2000 RPM in neutral. Is it the same with the clutch pushed in? That would rule out the trans input shaft or other issues im there.
I'd probably pull off all the belts and start it for a few minutes just to rule out the accessory drive items.
I have no idea how much vibration the wrong balance flywheel would make, or where you'd feel them most in the RPM range. Unfortunately I don't think there's a way to check without actually looking at it, even then unless its marked....
I'd probably pull off all the belts and start it for a few minutes just to rule out the accessory drive items.
I have no idea how much vibration the wrong balance flywheel would make, or where you'd feel them most in the RPM range. Unfortunately I don't think there's a way to check without actually looking at it, even then unless its marked....
I don't think i've tried revving it in neutral and pressing the clutch in. I will give that a go. Only done it in neutral with clutch out so far i think.
Last year i had a local shop quote me (roughly) $2,500-4,500 for the rebuild, with the wide spread based on parts supplied vs them supplying and any additional labor said parts would require.
And, unfortunately, I aint doing an engine swap. Took me like a month to the lower control arms haha plus i'm not even living at my house right now and don't have a garage.
I guess my other option is to just keep driving it, hope i don't damage anything by doing so, keep cleaning/swapping plugs, and wait until the house is done and i'm back with the garage and MAAAAAYBE try removing the engine. Would be a good learning experience, but also a lot of work.
If you talk to them again, ask them what it costs to just go 331. It's probably $600ish more if you're replacing pistons (for whatever reason).
302 → 306 Short Block Rebuild (Boost-Ready Street Build)
| Category | Item | Low ($) | Typical ($) | High ($) | Notes |
|---|---|---|---|---|---|
| Parts | 4.030 Pistons (9–9.5:1) | 350 | 550 | 850 | Forged preferred under boost |
| Piston ring set | 100 | 150 | 250 | File-fit moly rings typical | |
| Rod bearings | 50 | 75 | 120 | Clevite / King | |
| Main bearings | 60 | 90 | 150 | Size depends on crank polish | |
| Cam bearings | 25 | 40 | 70 | Always replaced | |
| Freeze plug kit | 15 | 25 | 40 | Cheap insurance | |
| Oil pump + pickup | 70 | 120 | 200 | Melling standard or HV | |
| Full gasket set | 120 | 180 | 300 | varies by brand | |
| Rod bolts (ARP recommended) | 80 | 120 | 200 | Often required for rod resize | |
| Parts Subtotal | 870 | 1,350 | 2,180 | ||
| Machine Work | Hot tank / clean / inspect | 120 | 180 | 300 | block prep |
| Bore + torque plate hone (.030) | 450 | 650 | 850 | required for 306 | |
| Deck block | 200 | 275 | 350 | ensures compression consistency | |
| Install cam bearings | 80 | 120 | 175 | ||
| Crank polish | 60 | 100 | 150 | assuming crank reusable | |
| Rod reconditioning | 160 | 240 | 350 | resize big ends + check straight | |
| Press pistons on rods | 80 | 120 | 180 | not needed with floating pins | |
| Balance rotating assembly | 250 | 350 | 500 | important with boost | |
| Align hone mains (if required) | 0 | 250 | 450 | many blocks pass inspection | |
| Machine Subtotal | 1,400 | 2,285 | 3,305 | ||
| Assembly | Short block assembly (optional) | 0 | 500 | 800 | if shop assembles |
| TOTAL (DIY assembly) | 2,270 | 3,635 | 5,485 | ||
| TOTAL (shop assembled) | 2,770 | 4,135 | 6,285 |
Expectation
Most boosted street 306 short blocks end up around:$3,200 – $4,200
if you assemble it yourself and nothing catastrophic is discovered.
That assumes:
crank cleans up with polish
block doesn’t need align hone
rods are reusable after resizing
These are very common upgrades once boost is involved.| Upgrade | Cost |
|---|---|
| ARP main studs | $120–160 |
| ARP head studs | $180–250 |
That’s a great breakdown, thank you.
If I go 331 (like my last fox) I might as well stay NA and do the whole H/C/I with that and hold onto the supercharger until I can figure out a tuning option that will at least pass SMOG. Right now that’s my biggest setback with trying to build out a plan. I’m like limited on what I can do.
Quarter horse I think is my only option because it (as far as I know) can retain emissions equipment functionality, or else I would be going megasquirt which seems like the easiest plug n play aftermarket option, but doesn’t control any emissions stuff.
Well I finally got a compression tester.
Couple questions:
1. Do I need to remove all the spark plugs to test a single cylinder, or can I just remove the one plug for #7?
2. Do I need to pull a fuel pump fuse or mess with disabling the fuel pump?
I know I should be testing all cylinders but due to lack of time I’m gonna start with just the problematic one.
Couple questions:
1. Do I need to remove all the spark plugs to test a single cylinder, or can I just remove the one plug for #7?
2. Do I need to pull a fuel pump fuse or mess with disabling the fuel pump?
I know I should be testing all cylinders but due to lack of time I’m gonna start with just the problematic one.
Was kind of back to thinking about the engine rebuild… one quick question is regarding roller rockers. With the TFS twisted wedge 170cc heads, stock bottom and stock cam, should I run 1.7 rockers to gain a little bit of extra lift with with the HO cam? ChatGPT says lift will be .472 with the 1.7’s as opposed to .444 with the 1.6’s when utilizing the stock cam. And also just verifying I need 7/16” stud mount rockers?
If you do all of that, and add boost, I might be worried about whether the springs are up to the task.
I don't know what springs come with those heads either or if you selected something else.
I don't know what springs come with those heads either or if you selected something else.
Couldn’t find too much information about what “upgraded valve springs” means in the description except for this sentence from trick flows website:
Assembled Twisted Wedge 170 cylinder heads arrive ready-to-run out of the box with top-quality valvetrain components to ensure great durability and longevity. This includes stainless steel valves, bronze guides, PAC Racing valve springs, thread-in 3/8" or 7/16" rocker studs, and chromoly retainers.
Also I guess you can do either 3/8 or 7/16” stud mount rockers?
Edit: ChatGPT says:
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Is Scorpion a good brand?
Or should I keep as much as I can Trick Flow if possible to pair with the heads? The TFS 1.7 rockers are like a $100 more.
Or should I keep as much as I can Trick Flow if possible to pair with the heads? The TFS 1.7 rockers are like a $100 more.
Is Scorpion a good brand?
Or should I keep as much as I can Trick Flow if possible to pair with the heads? The TFS 1.7 rockers are like a $100 more.
I run Scorpions in my rig. I had to modify the oil baffle on the stock valve covers. Not sure if you will have to with the TFS heads though.
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