Need engine rebuild advice

[cwrandolph]

I need some help to plan the rebuild of my ’91 HO 5.0. It’s bone stock now and has under 50K miles on it. Great oil pressure, no ticks or knocks. Not looking to build a monster engine. I want it to behave well on the street.

Here’s the parts I have gathered so far:
Trick Flow Twisted Wedge 170 heads (as-cast)
Scorpion 1.6 ratio roller rockers
GT40 Tubular intake manifold
65mm throttle body
Bullet style mass flow meter for 24lb injectors (also have 24lb injectors)

Planning to stick with:
OEM distributor/ignition/ A9L ECM
OEM balancer (brand new)

My original plan:
Tear the shortblock down, light hone on the cylinders & reuse the pistons since it’s got low miles (and they are forged). Hot tank the block, all new bearings, rings, new blueprinted std volume oil pump. ARP head bolts & oil pump drive. New timing chain set. Balance rotating assembly.
With this plan, I am limited to the lift of the cam due to the OEM pistons. (I believe that around .500” valve lift is the max.)
My questions:
Which cam would you recommend for this setup?
Possible to notch pistons for TW valves?
HP range?

2nd scenario
Same as above but bore .030” over and go with new pistons to accommodate the Twisted Wedge valves. I can run a higher lift cam with this option.
My questions:
Which cam would you recommend for this setup? (remember – street friendly)
Max compression ratio? (want to stay with pump gas)
HP range?

3rd scenario
Same as above, bore .030” over and go with a 331 stroker kit with pistons to accommodate the Twisted Wedge valves.
My questions:
Would this increase in displacement be too much for my heads & intake?
Guessing I would need to go to 28oz imbalance? (new balancer & flywheel)
Which cam would you recommend for this setup? (remember – street friendly)
Max compression ratio? (want to stay with pump gas)
HP range?

Other info: 4 into 4 headers, 3.55 rear, T5Z trans.

Looking for advice - advantages & disadvantages. Let me know what you think.

[JKleiner]

Twisted Wedge heads, Trick Flow stage 1 cam and OEM pistons with stock reliefs play well together and make for a nice combination. Put out the extra $$ for the upgraded springs though. I used a Street Heat intake with 70 MM throttle body and 24's. It makes great low RPM torque but will still pull hard up to the 6,250 rev limit. I'd expect the same head/piston/head combo with your GT40 intakes hould perform similarly.

Jeff

[1cobra]

Hi,
Sounds like a good street setup, the T F #1 cam is good to 5500 rpm.
'91 5 liters have hyper pistons, forged were 87 and 88.
Step up to a 331 and bigger cam but would only get you 20% more hp and not very good street manners. The gt40 intake will max out at 350 HP so you would need a trick flow or other intake and bigger injectors/TB and mass air.
good luck,
Perry.

[Michael Everson]

Just my opinion, but with less than 50,000 miles, I would leave the short block alone.
Mike

[cwrandolph]

Originally Posted by Michael Everson

Just my opinion, but with less than 50,000 miles, I would leave the short block alone.
Mike

Thanks Mike. What about getting it balanced? Is it worth it to tear it down to get it balanced?

[cwrandolph]

Originally Posted by 1cobra

Hi,
Sounds like a good street setup, the T F #1 cam is good to 5500 rpm.
'91 5 liters have hyper pistons, forged were 87 and 88.
Step up to a 331 and bigger cam but would only get you 20% more hp and not very good street manners. The gt40 intake will max out at 350 HP so you would need a trick flow or other intake and bigger injectors/TB and mass air.
good luck,
Perry.

Perry,
I'm pretty sure that the 5.0's had forged pistons through '92. They switch to hyper pistons in '93. Doesn't look like I will be going the stroker route. Probably will stay with the original rotating parts unless I find something strange when I tear it down. Thanks for the advice.

[Michael Everson]

I really don't see any reason to for a street car. I am no engine professional though. I just opened up a 302 with 76,000 miles and it was nearly perfect. I did replace the main and rod bearings, but they didn't need it.
Mike

[JKleiner]

Originally Posted by 1cobra

'91 5 liters have hyper pistons, forged were 87 and 88.

I believe you are mistaken Perry. As cwrandolph mentioned they were forged thru 1992. 1993 and later are Hyper.

Jeff

[1cobra]

Hi,
My 87 notchback (225 hp)was forged, I turbo'd that one.
My 91 notch (215 HP)was detuned from the factory,probably for emissions, hyper pistons and the cam was a 208* not the 215* that was is in my '87. Also had steel shim valve cover gaskets so there were a number of changes they didn't advertise like the front wheelwells were slightly larger to fit the 16" wheels and tires.
Mike is probably right, leave the shortblock alone and build on it.
Perry.