Bb Chevy Aluminum Cylinder Head - 316cc - Assembled Reviews

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Big-Cake Heads Shootout - The Large O Vs. The Big R

Oval ports and rectangular port heads

2 issues dorsum, we subjected a 468-inch big-block Chevy to a variety of unlike oval-port cylinder heads, ranging from stock peanut-port-style heads to full CNC-ported versions (see "The Big O"). In that story, nosotros attempted to dispel the myth that any powerful big-cake combination must include rectangular-port cylinder heads. Equipped with the right oval-port heads, the 468 easily exceeded 600 hp on the engine dyno. Virtually of the oval-port heads tested in part 1 offered airflow that would back up another 100 hp on the right combination.

Contrary to popular stance, our combination was limiting the potential of the oval-port cylinder heads, not the other way around. It is true that all of the factory performance big-blocks sported rectangular-port heads back in the twenty-four hours, but much has changed since the get-go muscle car era. Not only does a adept ready of aftermarket oval-port heads outflow the factory rec-port stuff, it does so with reduced port book. Big, lazy ports are ideally suited for neither performance nor street utilize, while smaller, efficient ports offer the best of both worlds. Nowhere was this more evident than in the fact that a couple of manufacturers chose to supply oval-port heads over again on this larger (and more powerful) 496 examination engine.

A mutual stroker displacement, our 496 was the issue of combining a 0.060-inch overbore with a 4.25-inch stroker crank. Our BBC rotating assembly came from the experts at Scat Enterprises. The BBC combination featured a 4340 forged steel crank combined with a set of matching 6.385-inch, I-beam rods. We chose a Scat crankshaft design specifically for our late-model, ane-slice, four-commodities, Gen-6 block. The Scat crank and rods were combined with a ready of forged pistons from JE. Offered every bit part of their SRP line up, the JE Pistons featured 18cc domes to produce a static compression ratio of 10.0:1 with typical 120cc combustion chambers.

The short-cake was built not to maximize power production, but rather to demonstrate what is possible for street utilise in a performance driver. We wanted all of our testing to exist run on pump gas, and then we kept the static compression at a reasonable level. L&R Automotive was responsible for machining and balancing of the combination, while Total Seal came through with a prepare of performance rings to ensure proper sealing.

The displacement ensured that our 496 would exist more than powerful than the 468 used in role 1, but nosotros hedged our bets with the installation of a wilder cam profile as well. Balancing the street/performance theme, we chose a pocket-sized solid roller profile from Comp Cams. The 300BR-14 offered 0.652 lift, a 255/262 duration split and 114-caste LSA. To work in the Gen-6 block, the cam was teamed with a fix of 0.300-tall solid roller lifters and a double roller timing chain.

Since the cam and timing concatenation were designed for a Gen-4 block, it was necessary to eliminate the factory cam retaining plate in favor of a traditional cam button. The swap also required the use of a custom front cover (PN217) from Comp Cams to provide the necessary room for the double-roller concatenation (factory Gen-6 covers must be run with a unmarried-roller chain).

Finishing touches on the test mill included an Edelbrock Victor Jr. 454-R intake, a Holley 950 HP carb and SFI-approved, neutral damper from Procomp Electronics.

Prior to running the test engine, all of the heads were treated to flow demote testing to correlate the catamenia potential to the power gains. In truth, heads similar the Brodix BB-iii Xtra O offered over 400 cfm--enough to support more than 800 hp. Nosotros were just scratching the surface or their potential with our 496 street/strip combination. After bench testing, we subjected the heads to port and sleeping room volume measurements. Since the compression ration is a function of the sleeping room book, sleeping room size has a significant consequence on the power curve (to the tune of 3-iv percentage per betoken). Measurements indicated that our test heads varied profoundly, from a depression of 107cc to a high of 123cc. Bear this in mind when viewing the power numbers.

It is again worth mentioning that though this was originally to be a rec-port-simply head exam (to follow the oval-ports tested in office 1), some of the manufacturers supplied oval-port heads for this 496. Don't look down yous noses at oval-port heads, equally testing from both stories suggests that if anything, oval is the new square.

Examination 1: Stock GM 088 Iron

Prior to running any of the aftermarket heads nosotros had to found a baseline by running the stockers. We chose a fix of 088 castings that featured 316cc intake ports, 121cc exhaust ports and 123cc combustion chambers. The airflow information suggested that the stock fe heads would back up over 650 hp, merely on this 496, the heads managed to produce peak numbers of 630 hp at 6,600 rpm and 577 lb-ft of torque at five,300 rpm. While 630 hp would make a serious street motor, nosotros would see that the right head selection on this application would add together almost 100 hp to that total.

• GM rectangular port castings
• Retail Price-NA
• Intake Valve Size-2.nineteen
• Exhaust Valve Size-one.88
• Intake Port Vol-316 cc
• Exhaust Port-121 cc
• Chamber Volume-123 cc
• Superlative Power- 630 @ 6,600 rpm
• Summit Torque- 577 lb-ft @ v,300 rpm
• Avg HP (iii,500-half dozen,500)-532.iv
• Avg TQ (3,500-6,500)- 560.5 lb-
• TQ @ 4,000 RPM - 562.7lb-ft

Catamenia Data: CFM @ 28-ins
Stock 088

Lift	In	Ex
0.050	32	27
0.100	77	56
0.200	144	112
0.300	206	142
0.400	245	166
0.500	289	188
0.600	320	192
0.700	334	197
0.800	335	201

Test two: Summit Racing Iron

Many would dismiss the iron heads but for the weight savings, merely don't count them out, especially when you consider the price and performance. These rectangular port iron heads from Summit Racing offered surprising blindside for the buck. The Peak Racing head upgrade improved the power output of the 496 from 630 hp and 577 lb-ft to 688 hp and 607 lb-ft. This was all the more impressive considering the fact that the heads price just $750 bucks each, assembled. Toss in the fact that the Peak heads period only marginally better than the stock heads and share the aforementioned combustion sleeping room volume. If you are looking for iron heads on a budget, look no further than Acme Racing.

• Retail Price-$749
• Intake Valve Size-ii.25
• Frazzle Valve Size-1.88
• Intake Port Vol-309 cc
• Exhaust Port Vol-127 cc
• Chamber Volume-122 cc
• Peak Power- 688 hp @ 6,600 rpm
• Peak Torque- 607 lb-ft @ v,400 rpm
• Ave HP (3,500-6,500)-555.v
• Ave TQ (3,500-6,500)-582.i
• TQ @ four,000 RPM-563.three lb-ft

Summit Racing Iron
Period Data: CFM @ 28-ins

Elevator	In	Ex
.050	34	34
.100	69	69
.200	146	109
.300	204	155
.400	264	192
.500	309	223
.600	340	246
.700	323	262
.800	330	273

Exam iii: Procomp Electronics Rec-Port CNC

The aluminum heads from Procomp Electronics combined the largest port book and (nearly) height period numbers with the everyman retail cost. The intake port volume measured a sizable 369cc, while the exhaust checked in at 157cc. This caput configuration would be much more than at home on a larger displacement, college horsepower application, but how can yous debate with aluminum BBC heads that flowed over 400 cfm for around $600? Equipped with the Procomp heads, the BBC stroker pumped out 690 hp and 600 lb-ft of torque. Nosotros suspect the large port volume and sizable combustion chamber hurt torque and ability on this application, as many of the other heads featured smaller chambers and port volumes. We'd like to run across this caput strut its stuff on a high-compression 572, only for our 496, it was probable merely too big.

• Retail Toll-$625
• Intake Valve Size-two.xxx
• Exhaust Valve Size-1.88
• Intake Port Vol-369 cc
• Exhaust Port Vol-157 cc
• Chamber Volume-123 cc
• Height Power- 690 hp @ six,300 rpm
• Top Torque- 600 lb-ft @ 5,500 rpm
• Ave HP (iii,500-half dozen,500)-554.2 hp
• Ave TQ (3,500-vi,500)- 581 lb-ft
• Tq @ 4,000 RPM-568.3 lb-ft

Procomp Electronics BBC Rec-Port CNC
Menstruation Information: CFM @ 28-ins

Elevator	In	Ex
.050	35	31
.100	seventy	67
.200	152	132
.300	234	175
.400	294	206
.500	336	231
.600	364	251
.700	389	267
.800	403	279

Test 4: Trick Flow Specialties PowerPort 360 Heads

Like the Procomp heads, the PowerPort 360s from Pull a fast one on Menstruation Specialties were probably a tad on the big side for the 496. With intake ports that measured 357cc, the impressive PowerPorts would be more at home on a big-block exceeding 500 cubic inches. With superlative intake period numbers of 384 cfm, the heads we capable of supporting over 750 hp, but on our 496 manage 691 hp and 603 lb-ft of torque. The PowerPort heads shared the big (122cc) combustion chamber volume of the stock heads and came in at a cost-constructive $1,229 (through Height Racing).

• Retail Toll-$1229
• Intake Valve Size-2.30
• Exhaust Valve Size-1.88
• Intake Port Vol-357 cc
• Exhaust Port Vol-134 cc
• Chamber Book-122 cc
• Height Power- 691 hp @ 6,400 rpm
• Height Torque- 603 lb-ft @ 5,400 rpm
• Ave HP (3,500-6,500)-555.3
• Ave TQ (iii,500-6,500)- 581.9 lb-ft
• TQ @ 4,000 RPM-562.3 lb-ft

Trick Menstruation Specialties PowerPort 360 head
Catamenia Data: CFM @ 28-ins

Lift	In	Ex
.050	35	30
.100	72	61
.200	148	125
.300	217	168
.400	275	198
.500	325	227
.600	360	246
.700	376	261
.800	384	273

Exam 5: Brodix BB-3 Xtra 332

The new Brodix BB-3 Xtra 332 heads were non quite a rec-port head nor were they a conventional oval (or peanut) port head. They were somewhere in the center, more like a rectangular-port with rounded corners. In truth, use of the 454-R (rec-port) intake may accept hindered the power potential of the Brodix heads more than than others due to the port mismatch. 1 affair for sure is that the Brodix heads topped all comers in terms of airflow with peak numbers of 409 cfm. Capable of supporting over 800 hp, our 496 produced 705 hp and 624 lb-ft of torque. We would dearest to port-match an intake to these heads in an effort to interpret all that airflow potential into ability.

• Retail Price-$1840
• Intake Valve Size-2.30
• Exhaust Valve Size-1.88
• Intake Port Vol-335 cc
• Frazzle Port Vol-133 cc
• Sleeping room Volume-115 cc
• Peak Ability- 705 hp @ 6,400 rpm
• Height Torque- 624 lb-ft @ 5,200 rpm
• Ave HP (3,500-6,500)-574.6
• Ave TQ (3,500-half dozen,500)- 602.7 lb-ft
• TQ @ iv,000 RPM-585.vii lb-ft

Brodix BB-iii Xtra 33
Flow Information: CFM @ 28-ins

Lift	In	Ex
.050	33	31
.100	66	69
.200	147	120
.300	211	173
.400	273	221
.500	333	256
.600	380	277
.700	409	286
.800	403	296

Examination vi: Dart Pro 1 335

The Pro 1 proper name from Dart has always meant power and this examination illustrates that the proper name however carries some weight. For our street/strip 496 BBC, Dart supplied a set of its CNC-ported 335 heads. With catamenia numbers that reached virtually 400 cfm, the Dart Pro 1s were another prepare of 800-hp heads in search of a motor. The Dart Pro 1 heads featured rolled valve angles and raised exhaust ports to improve flow and ability, but remained compatible with stock accessories. Run on the dyno, the big-block produced 717 hp and 619 lb-ft of torque. Equipped with a smaller chamber shared by the AFR and Edelbrock heads, the Dart would probable be correct in the hunt for maximum ability.

• Retail Price-$2021
• Intake Valve Size-2.30
• Exhaust Valve Size-ane.88
• Intake Port Vol-303 cc
• Exhaust Port Vol-137 cc
• Chamber Book-122 cc
• Peak Power- 717 hp @ half-dozen,500 rpm
• Peak Torque- 619 lb-ft @ 5,600 rpm
• Ave HP (three,500-6,500)-568.0
• Ave TQ (three,500-6,500)-594.three lb-ft
• TQ @ 4,000 RPM-572.v lb-ft

Dart Pro one 335
Flow Data: CFM @ 28-ins

Lift	In	Ex
.050	34	29
.100	69	61
.200	148	125
.300	228	181
.400	294	219
.500	336	249
.600	376	271
.700	398	281
.800	399	289

Test 7: Edelbrock E-CNC 355

Edelbrock has stepped up in a large mode recently with new performance offerings and these E-CNC 335 heads are a perfect example. Proudly made in the United states, the Eastward-CNC heads offered plenty of flow, peaking at 391 cfm on the intake and 285 cfm on the exhaust. Sporting the smallest combustion bedroom of the bunch at 107cc, the Edelbrock heads produced the highest static compression ratio. Naturally this helped ability, allowing the E-CNC heads to produce 723 hp and 627 lb-ft of torque.

• Retail Price-$1,630 (required bound upgrade)
• Intake Valve Size-2.thirty
• Exhaust Valve Size-1.88
• Intake Port Vol-353cc
• Chamber Volume-107 cc
• Exhaust Port Vol-135 cc
• Peak Power- 723 hp @ 6,500 rpm
• Summit Torque- 627 lb-ft @ 5,600 rpm
• Ave HP (3,500-6,500)-573.v hp
• Ave TQ (3,500-6,500)- 599.nine lb-ft
• TQ @ 4,000 RPM-574.0 lb-ft

Edelbrock E-CNC 355
Flow Information: CFM @ 28-ins

Lift	In	Ex
.050	33	29
.100	73	61
.200	148	132
.300	224	185
.400	283	226
.500	334	252
.600	364	270
.700	385	278
.800	381	285

Test viii AFR Magnum 300 Oval

It takes more simply big flow numbers to make power, and these Airflow Inquiry heads proved that. In fact, when asked to supply rec-port heads for this exam, they opted to instead send over a prepare of oval-port heads. It new 300cc Magnum heads did not offer the highest peak catamenia numbers, topping out at 383 cfm (at .650 elevator), but when combined with exceptional mid-lift period and an efficient chamber design, the results were enough impressive. Power product is all about the combination of components working together and on this 496, the AFR Magnum 300 heads proved to be the optimum combination past producing 729 hp and 639 lb-ft of torque.

• Retail Cost-$1,559
• Intake Valve Size-2.thirty
• Exhaust Valve Size-1.88
• Intake Port Vol-300 cc
• Frazzle Port Vol-123 cc
• Sleeping room Volume-110 cc
• Peak Power- 729 hp @ half-dozen,500 rpm
• Peak Torque- 639 lb-ft @ v,400 rpm
• Avg HP (three,500-vi,500)-584.1
• Avg TQ (three,500-6,500)-611.4 lb-ft
• TQ @ 4,000 rpm-587.0 lb-ft

AFR Magnum 300 Oval
Menses Data: CFM @ 28-ins

Lift	In	Ex
.050	34	32
.100	74	62
.200	153	126
.300	233	198
.400	296	237
.500	345	263
.600	377	277
.700	371	288
.800	365	296

9 Our shortblock featured a 4340 forged steel crank and rods from Scat. The 4.250-inch stroker crank combined with the .60-over pistons to increase the displacement to 496 cubic inches.

21 The combustion bedchamber of each cylinder head tested was measured.

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Source: https://www.motortrend.com/how-to/sucp-1208-big-block-heads-shootout-the-o-vs-r/

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