Long-Rod Slant-6 - my build
Having learned from so many of you here (and on .org), I felt obligated to share how things worked out with my long-rod build.
The original writeup can be found HERE. Sound-clip HERE.
This long-rod 225 slant-6 rebuild (now @ 231 CID & 3.8L) uses the 198 engine connecting rods to facilitate the use of better sealing and lighter weight pistons & valvetrain components as well as mods to create a performance street cruiser (not a red-light racer). Emphasis was on producing high air velocity through the intake tract, reducing parasitic power loss throughout, and lightening the reciprocating mass where budget allows - with all these stealthy mods hidden behind an otherwise plain-wrapper engine.
In all, it worked out great! Pulls strong from about 1,500 and rides in the powerband nearly forever. With cable throttle control and an Edelbrock AVS2 carb, the tip-in is instantaneous and almost feels like it's injected. That said, the build was designed for deeper gears - which are planned in the springtime with an 8.25" differential swap (have it - from '74 Dart Sport) with 3:07 ratio (Jeep) gears. This will pick up the slack from off-idle and balance the powerband range.
All said, I'm stoked with the results. Very drivable, quite a lumpy cam at idle (while pulling 10.5 Hg of vacuum) and pulls strong - with a balanced chassis. It's not a package for everyone - but works for me...
Comments are welcome :)
Induction
Cylinder Head
Block
Ignition
Cooling
Transmission
Performance estimations are 235-HP & 280-Ft/Lbs. torque [conservatively] I wanted to dyno it at the shop - but with more custom parts and labor than expected (which is always expected), I ran out of budget. I'll chassis-dyno it someday...
Special mentions are due to @my68barracuda @halifaxhops @slantsixdan, @RustyRatRod Doug Dutra, Duster Idiot, Slantzilla, Dart270, Charlie_S, Greg Ondayko, Joshie225, Dart270, Rick Covalt, CNC-Dude, and many more for directly or indirectly educating me on the ways of the Slant (my apologies for any omissions).
Having learned from so many of you here (and on .org), I felt obligated to share how things worked out with my long-rod build.
The original writeup can be found HERE. Sound-clip HERE.
This long-rod 225 slant-6 rebuild (now @ 231 CID & 3.8L) uses the 198 engine connecting rods to facilitate the use of better sealing and lighter weight pistons & valvetrain components as well as mods to create a performance street cruiser (not a red-light racer). Emphasis was on producing high air velocity through the intake tract, reducing parasitic power loss throughout, and lightening the reciprocating mass where budget allows - with all these stealthy mods hidden behind an otherwise plain-wrapper engine.
In all, it worked out great! Pulls strong from about 1,500 and rides in the powerband nearly forever. With cable throttle control and an Edelbrock AVS2 carb, the tip-in is instantaneous and almost feels like it's injected. That said, the build was designed for deeper gears - which are planned in the springtime with an 8.25" differential swap (have it - from '74 Dart Sport) with 3:07 ratio (Jeep) gears. This will pick up the slack from off-idle and balance the powerband range.
All said, I'm stoked with the results. Very drivable, quite a lumpy cam at idle (while pulling 10.5 Hg of vacuum) and pulls strong - with a balanced chassis. It's not a package for everyone - but works for me...
Comments are welcome :)
- Spectre Perf. #98881 14" 180-degree dual-inlet, aluminum air cleaner assembly. To make this work, you need to use the base from Edelbrock #1221.
- Edelbrock carburetor #1901 Thunder AVS-2 @ 500CFM w/electric choke. Running mostly on the primaries.
- Offenhauser #5270 four-barrel manifold - modified for water-heating under the carb baseplate. Saves several pounds from OE. [vintage part]
- Remflex #6008 carbon intake/exhaust gasket
- Attaching studs have been replaced with same-size parts from McMaster-Carr #94358A270 with an allen-head recess. Nuts are mil-spec flex-top locknuts #99638A300.
- Lokar throttle #XTC1000HT & kickdown #KD2904HT60 cables with bracket #SRK4000 replace mechanical linkage
Cylinder Head
- Street pocket-ported bowls and short-turn radiused - with the goal of increasing air velocity but not volume. Otherwise just cleaned things up
- Elgin supplied Ford 289 intake (#I-1670 @ 1.78") & exhaust (#E-1669 @ 1.45") valves. Oversized in slant-6 terms - and with a smaller diameter stem (5/16 vs 3/8), with positive seals and further modified with a back-cut.
- Street performance valve/seat angles
- K-motion #K-800 valve springs. Used only the outer spring resulting in 110/280 pressure - to match the cam specs.
- Comp-Cams valve spring locks & retainers
- Hand-fitted rockers & spacers
- Rockers are OE and only required cleaning to ensure oil-flow
- Endurotec #AS0193 BigBore cylinder head gasket
Block
- Line honed + new cam & crank bearings
- Deck was just kissed for gasket seating without much material removal
- Bored to 3.445" to match pistons, bringing the displacement from 225-CID/3.7L to 231/3.8L
- Wiseco #PTS536A45 forged pistons. Installed using press-pin option for endurance. Static compression = 9.6:1 (91 pump-gas)
- Wiseco piston rings #8750XX [1/16, 1/16, 3/16]
- Chrysler connecting rods from 198-CID slant-6 - which are longer than 225 rods. The essence of a long-rod rebuild!
- ARP connecting rod bolts from a Pontiac SD-455 engine [yeah, they fit!]
- NOS oil pump #2808507 - standard pressure & volume
- Chamfer on the #1 crank bearing for proper timing chain oiling
- Chamfer on the lifter bores to increase oil pooling at the top of the lifter
- Crankshaft oil holes chamfered & journals polished
- Oregon Cam Grinding's #346 camshaft was custom profiled to use Ferrea's lightweight .904" lifters which require a custom ramp angle.
- Cam Specs: duration @ .050 234/228, Lobe Separation 106, Valve Lift .476/.479
- Ferrea lightweight mechanical lifters #LF1004 [66-grams each]
- CompCams pushrods #2497864-12
- True-roller timing chain - custom set through Elgin using the chain & crank sprocket from 440/426 Hemi mated to their HP cam sprocket for the slant-6
- Specta Premium #SP1051MP fuel pump delivering 4-6PSI @ 30-GPH [ample supply]
- Felpro and Mahle gaskets
- Driven GP-1 15W-40 Synthetic Blend High Performance Oil with Baldwin #BT216 filter (integral standpipe). The oil has a lot of ZDDP for use with flat tappet engines and runs super clean.
Ignition
- OE alternator - rebuilt to factory specs @ 50-AMP
- HiRev-7500 electronic ignition module [from Rick Ehrenberg]
- NGK Iridium spark plugs #97382 - which draw fewer AMPs to fire than other plug types
- NGK spark plug wires #6716122
- Rebuilt and custom-curved (Sun) distributor from @halifaxhops
- Pertronix #40011 Flame-Thrower coil, selected for its quick saturation which helps deliver more torque at lower RPMs.
- Mini-starter [from R Ehrenberg] which draws significantly less amperage and startup than the OE. It also saves several pounds.
- New ignition/engine wiring harness #HU226A from YearOne was installed to ensure continuity and full-system reliability.
Cooling
- Unbelievably - still running the stock radiator! Although, I doubt I'll be that lucky in the summer - so I'm on the hunt for an upgrade.
- 195F SuperStat Thermostat #STA45359
- 16-LB cap #10231
- Recovery Tank (soon)
Transmission
- Torqueflite 904 has been rebuilt & upfitted with HD internals including steels & frictions
- TransGo #TF1 reprograming kit installed
- Custom 2800 RPM stall high-efficiency torque converter with 9.5" impeller & turbine, Torrington bearings, 7/16" ARP 240-7302 bolts, and 4130 chrome moly steel drive hub & spline insert - by Edge Racing Converters
- Flexplate is from a 440 #200-1040 from 440source
- AFT+4 fluid
Performance estimations are 235-HP & 280-Ft/Lbs. torque [conservatively] I wanted to dyno it at the shop - but with more custom parts and labor than expected (which is always expected), I ran out of budget. I'll chassis-dyno it someday...
Special mentions are due to @my68barracuda @halifaxhops @slantsixdan, @RustyRatRod Doug Dutra, Duster Idiot, Slantzilla, Dart270, Charlie_S, Greg Ondayko, Joshie225, Dart270, Rick Covalt, CNC-Dude, and many more for directly or indirectly educating me on the ways of the Slant (my apologies for any omissions).
