Installing a Comp Cams 270H in Your Mopar 360: A Complete Guide to Cost, Power, and Installation Tips

Dropping a Comp Cams 270H into a Mopar 360 small-block is one of the most rewarding upgrades you can make for street performance. This camshaft delivers a noticeable bump in horsepower and torque while maintaining good drivability, making it a favorite among enthusiasts who want a rowdy idle without sacrificing daily usability. Whether you’re building a classic E-body or a truck, this guide covers everything you need to know — from the specs and costs to step-by-step installation and supporting modifications. By the end, you’ll have a solid plan to transform your 360 into a strong, reliable performer.

Understanding the Comp Cams 270H

The Comp Cams 270H is a hydraulic flat-tappet camshaft designed for small-block Chrysler engines, specifically the 273, 318, 340, and 360. It’s part of Comp’s High Energy series, which offers a balance of power and street manners. The 270H is a proven choice for Mopar 360s because it works well with stock or mildly modified induction and exhaust systems.

Specifications

  • Duration at .050" lift: 230° intake / 236° exhaust
  • Valve lift: .480" intake / .480" exhaust (with 1.5 rocker arms)
  • Lobe Separation Angle (LSA): 110°
  • RPM range: 1,500 – 5,500 (usable to 6,000 with good springs)
  • Recommended valve springs: Comp Cams 901-16 or equivalent

The 110° LSA produces a distinct idle with a mild lope that sounds aggressive without being obnoxious. Intake vacuum typically sits around 12–15 inHg at idle, which is enough to operate power brakes and accessories. This cam works best with a moderate compression ratio (9.0:1 to 10.0:1) and headers or aftermarket exhaust manifolds.

How It Compares to Other Cam Options

If you’re considering other grinds like the XE262H or 268H, the 270H offers slightly more top-end pull without losing too much low-end torque. It’s a step up from milder cams but still comfortable with a 2,000–2,400 RPM stall converter and 3.23–3.55 rear gears. For a street-driven Mopar 360, it’s often called the “goldilocks” cam — not too wild, not too tame.

Cost Breakdown of the Comp Cams 270H Installation

Installing a camshaft involves more than just the cam itself. A complete job requires new lifters, gaskets, timing components, and likely valve springs. Here’s a realistic budget breakdown for a DIY installation.

ItemEstimated Cost
Comp Cams 270H camshaft$300 – $400
Hydraulic lifters (set of 16)$150 – $250
Valve springs (recommended upgrade)$80 – $120
Timing chain and gears (double-roller)$60 – $120
Gasket set (valve cover, timing cover, intake)$50 – $100
Oil and assembly lube$30 – $50
Pushrods (check length requirement)$60 – $120
Labor (if not DIY)$500 – $1,000
Total (DIY)$730 – $1,160
Total (with labor)$1,230 – $2,160

Prices vary by retailer. Check current pricing at Summit Racing or Comp Cams for the best deals. If you’re on a strict budget, consider buying a complete cam-and-lifter kit that includes the cam and lifters for less than buying separately.

Power Gains: What to Expect on a Mopar 360

Actual horsepower and torque gains depend on your engine’s existing condition, compression, heads, intake, and exhaust. On a typical 360 with iron 1.88/1.60 valves, a dual-plane intake (like an Edelbrock Performer), and headers, the 270H can add 25–40 horsepower and 30–50 lb-ft of torque over a factory cam. The power peak moves higher in the RPM range, but the torque curve remains fat from 2,500 to 5,000 rpm.

Dyno Example (from Mopar Magazine builds)

A common combination: 1974 Mopar 360 with stock bottom end, 9.2:1 compression, Edelbrock Performer RPM intake, 750 cfm carb, 1.6 rocker arms, and headers. With the stock cam (2-barrel or 4-barrel truck cam), it made about 240 hp. After swapping to the 270H and tuning, it put down 315 hp at 5,200 rpm and 390 lb-ft at 3,800 rpm. That’s a solid gain that wakes up the engine without needing internal machine work.

For a full build with ported heads and more compression, gains can be even larger. The cam’s .480” lift is conservative enough for stock valve springs in good condition, but to realize the full potential, upgrade to dual springs and retainers.

Matching Your Induction and Exhaust

  • Intake: A dual-plane intake like the Edelbrock Performer or Weiand Stealth works best. Single-plane intakes shift the power band higher and can hurt low-end torque.
  • Carburetor: 600–750 cfm vacuum-secondary or mechanical-secondary, depending on your setup. Tuning the idle circuit is critical with the 110° LSA.
  • Exhaust: Headers (1-5/8” or 1-3/4” primary) with 2.5” or 3” collectors yield the best gains. If you’re stuck with manifolds, you’ll leave 10–20 hp on the table.

For more detailed dyno data, check out Mopar Muscle Magazine’s cam comparison tests.

Preparation: Tools and Parts You Need

Before pulling the engine or tearing down the front, gather everything. Missing a tool mid-job costs time and frustration.

Essential Hand Tools

  • Full socket set (3/8” and 1/2” drive, metric and SAE)
  • Combination wrenches (8mm–19mm and 3/8”–3/4”)
  • Torque wrench (0–150 lb-ft)
  • Harmonic balancer puller (Chrysler-specific, uses large bolts)
  • Camshaft installation tool (or long dowel to guide bearings)
  • Feeler gauges, timing light, piston stop (if degreeing cam)

Specialty Parts to Order

  • Comp Cams 270H camshaft (Part #20-215-4)
  • Hydraulic lifters – use Comp’s 812-16 or equivalent
  • Valve springs – Comp 901-16 or 910-16 for higher RPM
  • Double-roller timing set (Cloyes or Melling)
  • High-volume oil pump (Melling M72HV recommended)
  • New timing cover gasket, oil pan gasket, valve cover gaskets
  • Assembly lube (Cam Shield or white lithium grease for lobes)
  • Zinc additive for break-in if using conventional oil

Step-by-Step Installation Guide

These steps assume the engine is in the vehicle and accessible. For a first-timer, a weekend of work is typical. If the engine is out, the process is simpler.

Step 1: Remove the Radiator, Fan, and Front Accessories

Gain access to the timing cover by draining the coolant and removing the radiator, fan, and fan shroud. On A-body Mopars, the K-member may need to be lowered slightly to pull the oil pan, but often you can replace the cam without dropping the pan if you’re careful.

Step 2: Remove the Timing Cover and Chain

Take off the harmonic balancer and timing cover. Remove the timing chain and gears. Mark the original cam gear position relative to the crank gear to verify alignment later.

Step 3: Remove the Intake Manifold and Rocker Assemblies

The lifters must be removed, and they come out through the lifter valley. Remove the intake manifold, valley pan (if equipped), pushrods, and rocker arms. On some Mopar 360 heads, you may need to remove the exhaust crossover bolts.

Step 4: Remove Old Camshaft and Lifters

Use a long magnet to pull each lifter. Keep them in order if reusing – but with a new cam, always install new lifters. Slide the cam out carefully to avoid damaging cam bearings. A cam installation tool helps steer the lobes past bearings.

Step 5: Inspect and Clean

Check cam bearings for wear. If they’re scored or the engine has high mileage, replace them (requires an engine stand and special bearing tool). Clean the lifter bores and cam journals with solvent and a lint-free rag. Apply a generous coat of assembly lube to all cam lobes and bearing surfaces.

Step 6: Install New Cam and Lifters

Lubricate the cam journals and carefully slide the cam into place. Install the cam gear and timing chain, aligning the dots per the manufacturer’s specs. Mopar 360 timing sets typically use zero-degrees at the crank unless you degree the cam later. Install lifters with preload set by using an adjustable pushrod check tool. For hydraulic flat-tappet, aim for .020”–.040” plunger travel.

Step 7: Replace Valve Springs (If Upgrading)

If you bought new springs, remove the old ones with a spring compressor (on the head is easiest). Install new springs and retainers. Check installed height and shim if necessary. This step is often skipped but critical for the 270H’s higher lift.

Step 8: Reassemble and Torque

Reinstall the timing cover with a new gasket, harmonic balancer (torque to specifications), water pump, and accessories. Torque the intake manifold in sequence. Use a new gasket set and sealant where required.

Step 9: Prime the Oil System

Before starting, use a primer tool (or an old distributor shaft) to spin the oil pump with a drill. Ensure oil reaches the top end. This prevents dry starts and cam failures. Also rotate the engine by hand several times to confirm no binding.

Step 10: Initial Start and Break-In

Fill with break-in oil (high zinc) and start the engine. Run at 2,000–3,000 RPM for 20 minutes, varying the speed. Do not let it idle! This seats the lifters to the cam lobes. After the break-in, change the oil and filter. Check for leaks and adjust carburetor idle mixture.

Upgrading Supporting Components

A cam swap is the perfect time to replace parts that may be worn. Here are the top upgrades to consider alongside the 270H.

Valve Springs and Retainers

Stock Mopar 360 springs are marginal at .480” lift, especially with higher RPM. Upgrade to Comp 901-16 springs (seat pressure ~110 lbs, open ~300 lbs) or 910-16 for more aggressive profiles. Use hardened steel retainers and keepers to prevent breakage.

Timing Chain Set

Replace the old nylon or single-chain set with a double-roller timing set (Cloyes #9-3085 or equivalent). This eliminates stretch and improves ignition timing accuracy for years.

Oil Pump and Pickup

A high-volume oil pump ensures adequate oil flow at higher RPM. The Melling M72HV is a direct drop-in. Also inspect the pickup screen and replace the pickup tube O-ring if equipped.

Pushrods and Rocker Arms

Check pushrod length when using different head gaskets or aftermarket rockers. If you upgrade to 1.6 ratio rockers, actual lift becomes .512”, which requires even stiffer springs and clearancing of the valve guides. The 270H works fine with stock 1.5 rockers.

Tuning After Installation

Getting the most from the 270H requires carburetor and ignition adjustments. The 110° LSA creates more overlap, which reduces manifold vacuum at idle. You may need to drill larger idle air bleeds or adjust the idle mixture screws out further.

Carburetor Tuning

  • Idle speed: Increase to 700–900 RPM for stable idle (depending on converter stall).
  • Idle mixture: Turn mixture screws out until highest vacuum is achieved, then fine-tune by ear.
  • Power valve: Use a power valve rated 2.0–2.5 inHg below idle vacuum. For 12 inHg idle, a 10.5 power valve works.
  • Accelerator pump: You may need a larger shooter (31–35 cc) for crisp throttle response.

Ignition Timing

Set initial timing to 12–16° BTDC. Total timing should be 34–38° BTDC by 3,000 RPM. Use a vacuum advance can with manifold vacuum if you want better fuel economy. Adjust the mechanical advance curve with lighter springs to bring timing in earlier.

Break-In Procedure

Use a break-in oil with high ZDDP (zinc). If using conventional oil, add an additive. Do not let the engine idle during the first 20 minutes. Keep RPM above 2,000 and vary it. After 20 minutes, allow the engine to cool, then change oil and filter. Re-torque the intake manifold bolts after a couple of heat cycles.

Common Mistakes and How to Avoid Them

Even experienced builders make errors. Here are the most frequent pitfalls with a Comp 270H install on a Mopar 360.

  • Reusing old lifters: Flat-tappet cams must be used with new lifters. Old lifters cause premature lobe wear.
  • Not degreeing the cam: Manufacturing tolerances can shift timing. Degree the cam to verify intake centerline is within spec (usually 106°–108°).
  • Incorrect pushrod length: If you change heads or deck height, check lifter preload. Too much preload can cause lifter pump-up; too little can cause noise and wear.
  • Skipping the timing cover gasket alignment: A misaligned gasket can cause oil leaks at the front seal.
  • Using too short a break-in: New flat-tappet camshafts need a proper break-in. Rushing this can wipe out the cam in minutes.

Conclusion

The Comp Cams 270H is a smart upgrade for any Mopar 360 that sees street duty. It provides a noticeable power increase, a pleasing exhaust note, and remains daily-driver friendly when paired with a proper converter and gearing. While the installation requires careful preparation and attention to detail, the payoff is a significantly more exciting engine. By budgeting for all supporting parts, following a thorough break-in, and tuning the carburetor and timing, you’ll get years of reliable performance. For more information, visit Comp Cams or browse build threads on For A Bodies Only for real-world experiences.