58 Rebuild begins

[3483x2]

After decades of putting my project on the back burner, I’m finally motivated to make great strides towards finalization. With that, brings the reality of a plethora of decisions to best approach this project with all the available innovations of today. Operating with 10K budget, I believe I can make some significant strides towards success.

The Goal: Beginning my classic car journey, I could easily identify myself then best as a purist, but over time I softened my approach yielding to the benefits of the innovations of today’s technology. EX. Paint vs Powder Coat, Carb vs. EFI excreta

The best project result I can describe today would be myself being after a respectable 58 Impala Convertible restoration capturing the vibe of the era allowing for the 348 to breath as it should with some smooth creature comforts and dodging as many high performance headaches as possible.

Drive train breakdown consists of a 348 Block => (TH 350, 200R4, 700R4) => 3:36 Posi (I might switch to 3:08 Ring Gears) in the Posi Case

The Tale of 2 Blocks:

Block 1: My original purchase included a 348 HA Tri Power block regretfully plagued with freeze cracks. The 3X2’s intake, carbs, plumbing & and Air Cleaner are now restored to completion. I did have a Black-Smith buddy take it and did a good job mending the block. I also invested in enough cast stitching material to complete if I choose with this block as an option. My main concern is going forward with the block and dealing with the ethanol issues plaguing a 3X2 setup in today’s environment.

Block 2: I’ve been fortunate enough to land another ‘58 4 BBl 348 dated coded to match the car which I’m leaning towards going with as an EFI build.

EFI: As mentioned above, building the 348 4 BBL block and going with a Sniper EFI 550-520 setup while dressing up the top end with a ’58 4 BBL Air cleaner. To complete the system, I’d also integrate an Edlebrock 7158 intake and convert the distributer & coil to a Holley HyperSpark setup taking advantage of solid spark technology. Integrating a matched EFI ’58 tank housing the 255 LPH fuel pump spares me a tank replacement I was going to get anyway.

Good news is over the years I’ve already acquired I’d say about 90% of the engine components needed to complete either 348 block refresh.

My cam choice specs are much milder than most here would prefer, but my build vision never embraced a “rattling window” build anyhow. Even a standard 348 build has enough performance to be regarded with admiration IMO. The main constraint I now see with the cam selection I made would be the 4800 power range and 9.5:1 compression limits. But factoring with an EFI build, I believe matches the vibe I’m seeking. The only other notable mods are Scorpion rockers and Stainless valves.

Company​

Part #​

Gross Valve Lift Intake w/1.75​

Gross Valve Lift Exhaust w/1.75​

Valve Lash Intake Exhaust (Hot)​

Valve Duration Intake​

Valve Duration Exhaust​

Duration @ .050 Intake​

Duration @ .050 Exhaust​

Centerline Intake​

Centerline Exhaust​

Timing Intake Open BTDC​

Timing Intake Closed ATDC​

Timing Exhaust Open BBDC​

Timing Exhaust Closed ATDC​

Lobe Separation​

Power Range​

Idle Type​

Application​

Camcraft​

409-1212-10A4 HCR​

0.481​

0.481​

HYD​

0.262​

0.262​

212​

212​

0.106​

0.114​

0​

32​

40​

-8​

110​

800/4800​

Smooth​

Up to 9.5:1​

Pistons: I am in the market for a fresh set of pistons & rings once the wall measurements of the block I choose to go with are confirmed. Both blocks have seen only light use and expect either block will clean up @ either STD or at worst 10 to 30+. Most recommendations here recommend going with forged pistons, but the only forged piston options I’ve seen so far have been in the 10.5:1+ category. Am I missing anything?

Transmission: Options are to go with anything than a 2 Spd Power Glide which only serve to stifle the power train I’m after IMO. A TH350 would be the easiest fit, but both 200r4 or 700r4’s offer interesting cruising benefits difficult to ignore. Whether it’s worth fitting a 200r4 or 700r4 into a ’58 X frame is worth the hassle remains a question. Converting to any of the above transmissions require cradle mounting, drive shaft replacement & linkage modifications, but any transmission conversion is proving to be an essential element of the drive train results I believe I’m after. Of course, matching the correct stall converter after the drive train math is identified and confirmed will yield greater benefits.

Rear End: As mentioned above, fitting my existing Posi with a 3:08 ring & pinion gears would be a real “bang for the buck” modification yielding improved cruising speeds with lower RPM gearing. I like the notion of keeping the external P case in tact while enjoying the 3:08 performance.

Power Brakes: The original Treadle Vac power brake system pales in comparison to any Disk Brake / Dual Master Cylinder Pwr Brake setup IMO. Does anyone still offer a Disk Brake option where the original ’58 rims can still be used?

 

[Murphdog]

A couple things come to mind for me and I realize you are wanting to keep this "stockish". I think the 58 block/heads lack some additional spark plug?? cooling/water passage holes. Don't know if this should be/is a concern. With a stockish build maybe not. If you keep the R's under 5500 or so I would be satisfied with cast pistons. Don't know if you can get a cast piston tall enough to create a real quench. If you can get to a .040/.050 quench it should work great @ 9.5ish CR with 91+ gas. Your cam choice is mild, but you said you did not want a "window rattler". I think it could benefit from a bigger exhaust lobe. Normally not a fan of straight pattern cams. Sound like you are on a path to a strong, calm, every day driver build. Only other thing is you might keep an open mind to a 409 crank, doing a 380 build that Don Jacks likes and could be an upgrade with virtually no additional cost. The extra cubes & torque sure won't hurt. Happy building!
Jeff

 

[scott hall]

If your block is cast after February it should have the spark plug cooling wholes I believe. They might not be drilled in block. Look at the numbers of heads and block. Give Jack Gibbs a call at 409 Performance. He’s in your state.

 

[La Hot Rods]

@1958 delivery sell a disk brake kit to work with the factory wheels.

 

[3483x2]

Thanks all. I didn't say in the intro, but I'll say here & now that I've seen the 24+ 348 build tips and expect to check each off as I move through the build. FWIW, both block castings are 3751872 GM1 with 3732791 GM2 head castings in early March '58
This leaves both blocks available to be punched out for cooler water jacket flow. Great call out!
@ scott hall - Gonna get on Jacks calendar asap and bang out thoughts and carve schedules asap. Thx
@ La Hot Rods - PM'd 1958 Delivery. Yay

 

[scott hall]

I don’t think the the heads have the cooling ports. The blocks might have the pads to drill the holes but then you’ll have a leak. Check head fast against the head to see for sure. If that makes since

 

[oldskydog]

791 heads don't have the water jackets so you will need later heads if you want spark plug cooling.

 

[3483x2]

Doh! I knew that! Pads can be drilled, 791 heads can't. Don't I feel like a shaved tail Louie. Glad I'm here so you guys can keep me real.

 

[3483x2]

OK... Revisiting Engine options, I'm still leaning towards rebuilding the 4 BBL block with EFI.

Since my March block can be drilled for water passages, Edlebrock offers aluminum 348 heads which do accept water passages.
Moreover, I see the EDL-60815's offer larger valves over the Standard Chevy 791's which would increase breathing which is one of the goals I'm after. Anyone have experience with these heads?
Yeah the Heads are pricy, but seems to me locating & building 3758379 heads for cooling still constrain the valve openings to standard 1.94 Intake and 1.66 Exhaust.

Thoughts and ideas are appreciated.

Here's the build parts list I've compiled so far:

Category	Description	QTY	Part #	Value	Code	Total Cost
Block	348 Block Valve Intake 1.94, Valve Exhaust 1.66		3751872 GM 1		C1058	$8,393.89
Engine	Piston Set	1		TBD	measure	$0.00
	Push Rod Set	1		TBD	measure	$0.00
	OEM CRD1053A 1958 Impala/Full-Size V8-348, Radiator	1	92626110	$582.99		$582.99
4 BBL	Holley Sniper EFI 650 HP Super Sniper Fuel Injection Systems 550-520	1	550-520	$1,474.95	425550520	$1,474.95
Manifold	Performer RPM Big Block Chevy W-Engine Large Port Intake Manifold	1	350-7159	$549.00		$589.00
Manifold	Intake Manifold Gasket for 1958-1965 348/409 "W-Series" Chevys	1	7240			$36.95
Head	Edelbrock Performer RPM 348/409 Chevy Cylinder Head Valve Int 2.19, Valve Exh 1.72	2	EDL-60815	$1,539.95		$3,079.90
	(Stainless Valves & Springs)
Distributer	HYPERSPARK EFI Distributor, GM 348/409	1	565-320BK	$349.95		$349.95
	SNIPER EFI HYPERSPARK CD IGNITION BOX	1	556-151	$315.95​		$315.95
	SNIPER EFI HYPERSPARK IGNITION COIL	1	556.152	$46.15​		$46.15
	HYPERSPARK PLUG AND PLAY MAIN HARNESS	1	558-328	$149.95​		$149.95
Fuel Tank	58 Impala EFI Fuel Tank kit - 255 LPH Pump	1	102-6680-04	$586.00		$586.00
Transmission	TH350	1	TBD	$2,000.00		$2,000.00
	Torque Converter	1	TBD	$200.00	Stall Speed?	$200.00
Brakes	Chevrolet Passenger Cars Front Disc Brake Conversion- Original Wheels	1	58RRHOWP	$599.00	58 Rims	$599.00

 

[3483x2]

Found a vicinity local shop to do my build. Shop will do the 4BBL block to an EFI build as above.
Shop will handle the lower end build. (Crank, Cam & Pistons) Going to have them open the water passages on the block for cooling.

The heads & intake will be order matched to the above Edlebrock aluminum components resulting in increased upper block valve sizing for healthier breathing which is one of my primary goals:

Valve Intake

1.94

Valve Exhaust

1.66

Valve Intake

2.19

Valve Exhaust

1.72

Following the block inspection the shop will determine best piston sizing.
Regarding piston compression, I'm inclined to stay 9.5:1 or 10:1 as a max preference since I really don't want to mess with gas additives and such.

If I'm off base here regarding either my cam or compression selections, sound off please. I can take it.

I'm also going to get the '58 348 HA block tanked and inspected. This block will soon be available as a long block offering. (Air Cleaner to Oil Pan)
Took stock today of all the hard to find matching parts and fixings I've squirreled away over the years to be offered.
Once the block is returned, I'll dry assemble, take pics and post the results.

 

[Don Jacks]

With the Edelbrock head,use the 10.5-1 piston.This combo should put your ratio right around 10.Upgrade your cam choice to Show Cars pn 0950[218-in.,224 exhaust]for aa good over all package .Build a quench area of no more than .040 for best results.

 

[3483x2]

Just discovered a major EFI plan set back.
On another site, I inquired about staying with the stock generator/PS pump and was advised to convert to an alternator for EFI.

**an 80a or better alternator, between the ecu demands and the elec fuel pump, you need a constant output rate, more than the generator can supply**

I remain committed to building the 58 4 BBL 348 lower end and leverage the Edlebrock 60815 Heads and 7159 Manifold for better breathing.
(Water jackets already opened to match the 60818 heads) Thx Cecil for the 348 TSB

I really was hoping to tap into the EFI tuning benefits and stability, but switching the generator to an alternator and redesigning Power Steering system strays too far from where I want the engine compartment to appear.

The only options I can think of would be somehow increasing the generator output (if that's even possible)

Anyone maintained the PS pump with an alternator option?

 

[oldskydog]

Convert to a 60 and later PS pump and go with the alternator in whatever amps you need.

 

[3483x2]

Will this work with my PS Pump? (Model 9029)

Classic Alternators

Generator, alternator, classic auto, antique auto

www.classicgenerator.com

If so, I'm back in the game.

 

[3483x2]

For 2023, most of my efforts can be attributed to securing EFI support and Digital Dash components.
Dakota RTX Dash, RLC Digital Clock, Holley EFI Interface, 348 Alternator, Front Power Brakes & Booster.

Never planned on the Alternator requirement, but Classic Generator hooked me up nicely in order to meet my needs to still house the PS pump.

Truly out on a limb here, but remain totally psyched about Dakota Digital's RTX Dash and clock offerings for '58s.
Having all those vital EFI digital elements available while still maintaining the 50's vibe truly makes feel like a kid in the candy store again.

1958 Chevy Impala RTX Instruments

Dakota Digital manufactures digital instrumentation and accessories for the automotive, motorcycle and car audio enthusiast.

www.dakotadigital.com

The 348 block remains at the shop awaiting tanking and cylinder size determination in order to secure pistons.
I'll be shaking their "monkey tree" to press on they're hold up following the holidays.

Next week, I'm ordering a set of heads from Bob Walla. Another welcome substitution/improvement to my original build plan.
Later in (spring?) of 2024 will come full glass replacement. Road trip for that stuff.

Furthermore, 2024 will be exploring my essential needs for an adequate spark. HyperSpark 348 Ready to run Distributer.
Unknown whether a Ignition Box would add value for my project. Plus, whether a power matched stock looking coil should be enough juice.
Or would I be cutting myself short there. Feedback invited.

EFI selection itself, I'm leaning towards Holley Terminator series mostly to retain stealth wiring/plumbing options and leverage an external ECU.
Housing the ECU where the old Treadle Vac tank used to be is my location of choice.

Inch-worming towards success...

 

[Don Jacks]

Are you planning to srrokr it? What are your thoughts on cam selection? This is looking to be sweet build.

 

[our1962]

They don't have non ethanol in Connecticut? I haven't put ethanol in any of my hot rods

 

[3483x2]

Don - Thx so much! To your question. No plans to Stroke it. My goals are to build a "snappy" EFI driven 348 with increased air and coolant flow.
Drivetrain: 348 EFI => TH350 => 336 Posi modified with a 3.08 ring and pinion.

Now more than ever, a matched cam selection would be the most essential choice at this juncture.
Having sought your guidance over the years, you always advised me to go with Show Cars 0950 grind over the Camcraft grind I had gotten from Charlie ages ago.
If the Show Cars 0950 grind can still be had, it still may be a contender. Lot's of delays in today's market getting parts.

Bob Walla did mention he has a grind in stock I may find interesting.
Given his expertise, if I can find a grind proven to work within the specs of the heads that he offers, It'd be foolish of me not to consider it.
Suffice to say, I'll be in contact with Bob next week to firm up details on purchasing the heads and get better details of what he has to offer.

Again, responsive and snappy throughout the power range is the performance goal I'm after without rattling the windows.

@our1962 - Agreed... Ethanol would be the main nemesis I seeking to counter with my EFI build.
That and the ability to dial in on real time performance tuning data.
Here in the east, I expect I won't be rid of the Ethanol plague any time soon.

Spark-wise, still researching whether the external ignition box would be a value add to what I expect to be a 350 - 375 HP build.
Seems like a Hyperspark 348 ready to run distributor & coil would do the trick unless I'm missing something.

 

[3483x2]

Ahhhh! Good news, not so good news. First, a overdue update.

The good:
Elected to go with a pair of Bob Walla heads over the Edlebrock 60815's
(Same valve size, water jacket advantages, but original GM push rod geometry) Plus, I believe BWR offers a more personal touch to our projects.
Bob also set me up with a set of IBeam connecting rods.
Edlebrock 7159 Intake rec'd
Converted to Classic Generator Alternator in order to support EFI demands. Date stamped and still allows attachment to PS pump.
Rec'd Hyperspark 348 565-320 Distributor and stock coil.

Not Engine related, but rec'd Dakota RTX Digital Dash and clock which I find to be a totally inspiring look along with remarkable functionality.

The not so good:
Just got a call today from the machine shop stating that although the block cleaned up and magged OK, they're sacking their operations and won't be going any further.
I suppose it's good they're telling me now since it would be best to find a shop better suited to stand by their work as opposed to one going belly up. What remains outstanding would be cylinder clean up work in order to determine piston sizing and an align boring of the lower end.

I'm at the point where I'll be etch priming and painting my heads an intake soon.
Wondering whether it's an OK time to also paint the block to seal the outside of the block keeping the the inners freshly lubed awaiting the work.

 

[Murphdog]

I would not suggest any painting of the block because when whomever gets done with the boring & honing / machining operations they should want to run it thru the spray washer again which will trash the paint. I would not want you to bring it to me painted because some of the aftermarket paints are a bear to get off in a spray cabinet. JMO.
Jeff