I. Street Use
1. Single Barrels
Any 170 cu. in. slant six having a small BBS carburetor (1-1/4" dia. venturi) will produce about 5% more power when the 225 cu. in. BBS carburetor (1-11/32" dia. venturi) is installed. These two carburetors can be identified by measuring their throttle bore diameter. The larger carburetor has a 1-11/16" dia. throttle bore and the smaller carburetor has a 1-9/16" dia. throttle bore. All 170 manual transmission jobs and the 1960 and 1961 170 with automatic transmission have the smaller carburetor.
2. Two Barrels
a. Two Barrel Conversion Available from MoPar
A two barrel set up (as used on the 225 cu. in. marine engine) is available from MoPar as follows:
- 1 - 2463849 carburetor
- 1 - E8467 manifold
- 1 - 2465310 air cleaner
b. Do-It-Yourself Two Barrel
The two-barrel carburetor from any 318 V-8 engine (without CAP Package) can be used as shown in Fig. 1 attached. [Ed: This figure is a crude hand drawing of an overhead view of the engine block, manifold, and carburetor plate. There is an arrow to the carburetor plate saying, "Plate shaped like 2 bbl. gasket welded on std. manifold." There is an arrow pointing from the carburetor toward the slant six block saying. "Carburetor float bowl points this way." Finally, there is a dimension from the center line of the carburetor plate bores to the cylinder head face (where the manifold meets the head) marked 7 3/8" inches.]
c. "B" Engine Two Barrel
The larger two barrel from a 361 or 383 can be installed as in item b. above. However, low speed driveability in cold weather may be unsatisfactory on the street.
d. Four Barrel for the Street
The AFB from the 273 power pack can be adapted to the 225 six cylinder. The four barrel bores must be centered upon the standard six cylinder inlet manifold's plenum chamber.
B. Compression Ratio
Up to .090" can be removed from the slant six cylinder head. The slant six cylinder head has an especially thick lower deck surface.
For example, removal of .090" will raise the compression ratio of a 225 engine from 8 to 1 up to 9.5 to 1. Removal of .090" will raise the compression ratio of a 170 engine from 8 to 1 up to 10 to 1.
NOTE: It is advisable to used the stainless steel head gasket from the 225 marine engine after milling the cylinder head. Also, the valve-to-piston clearance should be checked if the milled head is used in conjunction with a high lift camshaft.
C. Spark Advance
For street use, the total spark advance at engine speeds over 3000 rpm should be 30 to 32 degrees (check with the vacuum advance disconnected).
D. Valve Gear
1. All-around Street Cam
Marine engine camshaft #E7885M is the best all-around street cam. It is a 244-degree duration with .405" lift and 26-degree overlap. Standard slant six cam is 232-degree duration with only 8-degree overlap.
2. Super Street Cam
Hyper Pack Cam #2205620 (276-degree duration) is borderline for driveability even when used with a manual transmission and a high numerical axle ratio. The Hyper Pack cam should never be used with an automatic transmission.
3. Valve Springs
Heavy duty valve spring #1944554 should be used with the marine cam E7885M and must be used with Hyper Pack Cam #2205620 because of the valve lift involved.
Heavy duty valve spring retainers #2202546 must be used any time engine speeds of over 5000 rpm are attempted. BOth cam E7885M and cam 2205620 use standard tappets.
E. Exhaust System
1. Hyper Pipe
Exhaust pipe and muffler assembly #2208350 fits the Lancer through and including the 1961 model. This is a 2 1/2" dia. exhaust pipe and a "B" engine size muffler and offers several percent gain in output over the standard system.
On the '62 and later 170 slant six the rear pipe must be modified for clearance to back geared starter. 2208350 will clear the starter on all 225's.
2. Exhaust Manifolds
The best street exhaust manifold combination includes the front three cylinders from the standard manifold combined with the rear Hyper Pack header manifold. This allows the front three cylinders to provide carburetor heat which is necessary below 50 F ambient temperature. The back three cylinders exhaust through the Hyper Pack Header #2129900; and the Hyper Pack Exhaust Pipe and Muffler #2208350 can easily be modified to fit this combination.
II. Drag Strip
A. Stock Class
A MoPar Hyper Pack #2205573 (see list attached) was available for the 1961 Lancer. This kit can be raced in NHRA stock with the standard 8 to 1 compression ratio only. NHRA allows a combustion chamber minimum CCs of 53.8 CC. NHRA minimum piston top to block deck measurements are .141" for the 225 and .000" for the 170.
Based on experience gained since 1960, the basic Hyper Pack can be improved upon for modified drag racing as follows:
Three Weber dual carburetors 48 IDA will improve engine output nicely compared to Hyper Pack inlet manifold and carburetor on the slant six. Obviously a hand-fabricated inlet manifold would be required; one cylinder per Weber throttle bore.
2. Compression Ratio
Using 1965 - 1966 vintage gasoline quality, compression ratios between 12 and 13 to 1 should perform satisfactorily on the drag strip. "West Coast" pistons would be required to attain ratios this high. Step seal "Dykes" top piston rings should also be used because they lower engine friction at high speeds. "Slug" pistons should be fitted at .008" to .010" clearance.
3. Valve Gear
It appears that either the Racer Brown ST12 or the Iskenderian 1012B should perform well in fully modified engines. Obviously Iskenderian or Racer Brown push rods, retainers, springs and so on should be used. No slant six dynamometer work has been done at Dodge with these cams, but these cams have produced power very well in the Dodge Wedge Head
4. Exhaust System
Cylinders 1, 2 & 3 should exhaust through 1-5/8" or 1-3/4" O.D. pipes about forty inches long into a cloverleaf collector and then through a 2-1/2" O.D. outlet pipe much like current factory-sponsored Super Stock practice. Cylinders 4, 5 & 6 should have a duplicate system.
5. Big Valves
The standard 6 cylinder valves are 1.62" dia. inlet and 1.36" dia. exhaust. Bigger valves can be installed as follows:
a. Exhaust Valve (Oversize)
The 1957 Dodge V-8 exhaust valve #1827958 makes a very convenient oversize valve for the slant six. The head diameter is 1.5" or .140" oversize and the length is satisfactory. It is necessary to provide a clearance notch at the top of the bore.
b. Inlet Valve (Oversize)
The 1-3/4" dia. 163744 exhaust valve from the 1957 or 1958 Chrysler 392 V-8 can be made into a .130" oversize inlet valve. However, it is necessary to reduce its length by .270" and cut three more lock grooves down the stem. No bore notch is required for clearance for this oversize inlet valve.
6. Engine Oiling
For high-speed, fully modified engines provision must be made for more oil flow through the main bearings to the rod bearings. One way to achieve this is to groove the crankshaft (which unfortunately may result in crank breakage). A better way is to use upper main bearing shells in the main caps. (It will be necessary to file down the locating tabs to allow the grooves to align.) These tabs merely locate the bearings. The tabs do not prevent rotation; the inserts are "crushed" by the cap to prevent rotation.
The oil sump should be greatly enlarged so that the oil level is at least six inches below the crankshaft's path. At least six quarts capacity is necessary.
The truck 225 crankshaft (shot peened and not cold straightened) should be used for fully modified 225 slant sixes.
MoPar Hyper Pack Major Components
||Assy. - Camshaft
||Assy. - Valve Spring & Damper
||Assy. - Valve Push Rod
||Manifold - Intake
||Manifold - Exhaust - Front
||Manifold - Exhaust - Rear
||Assy. - Carburetor
||Gasket - Carburetor Flange
||Assy. - Air Cleaner
||Gasket - Air Cleaner
||Assy. - Clutch Cover & Pressure Plate
||Assy. - Clutch Driving Disc
||Gasket - Exhaust Pipe Flange
||Assy. - Muffler & Exhaust Pipe
Four Barrel Carburetor For All Slant-Six Engines
A carburetor that gives proper fuel mixture and distribution characteristics for the six-cylinder engine using a Hyper-Pak intake manifold or a modified standard intake manifold can be made from a Carter model 3854-S carburetor. This carburetor is used on the 1965 and later 273 cubic inch high performance engine. The modifications are as follows:
The throttle linkage will have to be fabricated to match the installation.
- Replace the metering rods with No. 16-177 rods. (.067 - .065 - .055" dia.)
- Replace the throttle side secondary jets with No. 120-181 jets. (.049" dia.)
- Replace the choke side secondary jets with No. 120-226 jets. (.065" dia.)
- Replace the primary venturi clusters with clutch No. 48-264S.
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