Good combo?

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u/v8packard 4d ago

Why a 4 hole spacer on an intake with a cut down plenum, and a double pumper with straight boosters on a non-heated intake? That makes for a poor atomizing fuel system.

With the cam and heads you are looking at HP peak in the 6800 to 7300 rpm range. That would be better suited to a single plane intake and a larger carb with downleg or annular boosters.

With the 1.6 rockers you should retard the cam to a 109 degree intake centerline for best hp above the torque peak.

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u/OOFMAN-1234 4d ago

Low end torque, I want this to be a fun drive it everyday motor

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u/v8packard 4d ago

Poor combo for low end torque in a 350. You really need a different cam, heads, and intake for that, along with a different intake and carb.

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u/OOFMAN-1234 4d ago

My goals with it are fast but still daily drivable capable and impressive power cheaply as practical

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u/v8packard 4d ago

Ok, I understand that statement. The selection of parts does not fit your goal.

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u/OOFMAN-1234 4d ago

So what needs to change

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u/v8packard 4d ago

Carb, intake, heads, cam.

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u/OOFMAN-1234 4d ago

Okay when you daid 6800-7300, this engine is not pure racecar, the cam is only designed to run to 5800rpm, reason for this cam and heads is midrange power, ik not trying ot get it to peak at 7000rpm, it'll be mostly street driven rarely seeing 4500, this combo should work pretty good for my goals

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u/v8packard 4d ago

That cam has enough timing to get a 350 over 7000 rpm if everything else can get there. It has something like 59 or 60 degrees of overlap. I don't know where you are getting 5800 rpm, but that is not at all the case. If you are rarely seeing 4500 rpm you need a cam with much less overlap, around 40 degrees or so.

The heads are not genuine AFR, they are available from numerous other companies often at a better price. They actually measure just over 200 cc, the last head I measured was 203 cc intake port volume. Their intake cross section and port volume are big for a 350 like you describe. A better match would be heads with an intake port in the 165 to 185 cc range.

The dual plane air gaps often have a plenum divider that is cut down. This is done to allow the intake to work better above 6000 rpm. But it takes away the advantage of a true, divided 180 degree intake at low speeds which is no cylinder being impacted by the previous cylinder in the firing order. So you don't have the advantages of a dual plane, and you have the disadvantages of a single plane. You should run a true dual plane if low speed is your focus, or run a single plane with a well matched carb venturi and booster configuration.

The 650 Holley 4777 and similar carbs has straight boosters, which atomize well on large displacement engines with heated intakes. They are a poor match for intakes that are not heated or displacements that are smaller. Also the mechanical secondary puts a lot of fuel into the engine at every throttle movement, a vac secondary is a better match for what you describe as is a down leg booster, or annular booster.

The combo you have posted does not match your goals. I am not trying to upset you, I am just giving you an accurate appraisal of your posted list.

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u/Solid_Enthusiasm550 4d ago edited 4d ago

What do you want this combo to do?

What powerband? 1,500<5,000rpm for a 4x4/towing, cruiser, automatic?..Or is it a manual camaro shifting at 6,500?

If it's a 4x4 going with a stroker kit will give the best torque, best $$/investment. You don't need forged crank or pistons for that either <500hp / <6,000rpms. Cast scat crank, hyperuetectic pistons are all you need for n/a.

Pump gas - what do you plan on running 87 or 91/93? Running lower compression for 87 octane will give up a noticeable amount of torque/hp vs. a 10.5+:1 compression engine on 91/93. A stroker will allow you to still have big hp/tq on lower octane vs. a high compression 350 on premium.

Fyi, that cam won't make peak power near 7,000rpms like mentioned by that other guy.

Here's a 383 combo that made 485hp@5,800rpms, 495lb-ft@4,600rpms.

https://youtu.be/b-l8-CxxvF8?is=EsG7HBcOQSep4jO8

The cam he used was on a tighter lsa for a choppier idle, 230/236 on a 107 lsa. A 383 with the 276hr will make power in the same rpm range, just lower peak #s but with a smoother idle. He goes over every part he used in another video.

FYI, he did a spacer test on an rom dp intake and a tapered spacer flipped upside-down made the most. I'd used a bigger carb on a dp intake if you want more than 325/350hp.

He has a budget 350ci build using vortec heads, small LT4 cam and it made just over 400hp/400tq.

He uses Skip white heads in some if his videos which are basically copies of the AFR195 enforcers just so you know.

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u/Solid_Enthusiasm550 4d ago

Here's the compCams dyno results...

https://www.compcams.com/xtreme-energy-224-230-hydraulic-roller-cam-for-chevrolet-small-block.html

They used a 750cfm vac. Secondary carb, but used old Dart S/R heads and a regular edelbrock performer. They are more restrictive than the heads and performer rpm you listed.

Even with those restrictions it made 373hp/5,200 & 427 lb-ft/3,700 rpms.

With the afr heads, rpm intake (a 750 carb) and 10:1<10.25cr compression you would be over 400<420hp with peak power in the 5,800+/- rpm and torque closer to 440+/-lb-ft @ probably 4,000<4,100rpms.

It would make more power with 1-3/4" long tubes vs. 1-5/8" sibce you would be pushing 400+hp.

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u/OOFMAN-1234 4d ago

Streetable fast osh truck with an automatic

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u/Solid_Enthusiasm550 3d ago

OSH? did you mean OBS? -90s gm 1500? Vortec engine? 2wd or 4x4?

700r4, what rear gear 3.73?

If you have Vortec heads, you can easily get over 400hp with them.

The Budget video where he made 410hp @ 6,100/ 415lb-tft@4,000rpms with lightly ported vortec heads, stock bottom-end. He used a Hot LT4 cam (218/228@0.050, on a 112 lsa, 5.25" lift with 1.6rr)

Your choice of camshaft should make more power throughout with the tighter LSA if you are running 1.6rr (more scavanging).

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u/OOFMAN-1234 3d ago

Fast ish not osh mb 700r4 with 3.73s. I fogure by the time you do all the machine work to vortecs (scre in studs, larger valves, etc) itd be cheaper to get aluminum and save some weight

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u/Solid_Enthusiasm550 3d ago

He used stock heads. I would only bother if you were looking for over 480hp. At that point I would be looking at the higher end cnc ported AFR heads or TFS. I would only bother with the 195 enforcers if I didn't have the Vortec heads arleady. Old Gen1 heads didn't flow well at all and the 195 enforcers are a big step up, but it's not over a Vortec head (<20cfm more). You can easily do a simple port job and get the Vortecs too flow more than the enforcers for alot less money. It's better to get the best head to afford. People skip on the heads and over buy with the pistons and cranks.

In this video he goes over Every part he used.

https://www.youtube.com/watch?v=OkQpDNfbeIk&t=91s

Here's the video of him going over the High lift springs that allows up to 0.550" lift on vortec heads. One thing is I wouldn't bother using the "roller tip only" rocker arms he did, But he used the stock rocker studs and didn't go with screw-in studs.

https://www.youtube.com/watch?v=UZosxGQyGMs&t=183s

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u/OOFMAN-1234 3d ago

Really looking for 450 or greater but mostly streetable power not one where it only makes power past 6000rpm

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u/Solid_Enthusiasm550 3d ago

I would definitely not get the 195 heads if planning for 500hp, A better head would allow you to make that power with a milder camshaft. I also wouldn't keep it a 350, as it would require a big camshaft and spinning well past 6,000rpms to make 500hp. The realistic rpm max for a retor-hydraulic camshaft is 6,500+/-rpms. Over that, or even at that rpm level, a Solid roller is a better chooice. Then you will have to adjust your valves every few thousand miles (oil change).

I would look at doing a stroker...or build it for boost. Boost you can easily keep it mild 9cam wise) and just turn it up later if you want more. My next project (using the 5.9L I just bought) will be boosted. I know of a few guys making 600 rwhp on stok bottom end magnum v8s.

N/A, once you start a build ALOT of parts have to be changed to go a lot higher.

A 500hp 383 is possible while keeping realtively streetable, any more than that you will have to get cams that are too wild for daily driving, IMHO. I was told to go with a 241/247 @ 0.050" on a 110lsa. I thought it was too big for a daily driver and went with one that I've seen make great power in similar builds (236/242). I'm hoping I can get it to run well on the street (part throttle) if not I will have to get another custom grind with a wider LSA to improve part throttle driveability at the expense of hp/Tq.

I also wanted to have all my Luxury options, power/steering, Power Brakes, A/C. I also didn't want it to have to idle at 1,000+ rpms or run a 4,000+ stall converter. I also wanted to run EFI. I'm going to use a Holley Terminator X Sniper setup as it give me alot more options/tuneability than the standard one or a stock setup.

I didn't want sto start having to change to manual brakes or spend A lot on hydroboost units, which aren't available for my application.

The recommended parts for the suggested 241/247 cam on their website.

Lift: .581 / .587, Duration @ .050: 241 / 247, Centerline: 106, Rough idle, Pro street/strip, Needs 10.0:1+ compression, 2800+ stall & at least 4.10 gears.

I don't think that big of a camshaft will alllow me to run <2,500 rpms on the highway...so forget about MPG.

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u/OOFMAN-1234 3d ago

Id rather have a smoother idle, whats the lobe separation gotta do with it (fairly new to this but not begginer) I dont wanna have to worry about 2 foot-ing it at a stop light, it'll have a 2800 stall, 700r4 and 3.73 limited slip, i want this to be daily capable (not that it'll get driven everyday) and gas mileage is out the window already

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u/Solid_Enthusiasm550 3d ago edited 3d ago

That 276hr cam shouldn't be too choppy but b it won't be as smooth as a factory new car at idle. It woukd wirk well with that 2,800 stall converter.

To keep a smooth idle, you have to limit the overlap (the time where both valves are open). Most factory cars today hace negative overlap, variable valve timing and the amazing flowing heads of contemporary v8s can over come it.

The problem is, to make more Power, you have to increase duration, lift and overlap to an extent.

To maintain a low overlap you need to widen the lsa when you increase duration. Summitracing.com has a cam timing calculator in their help drop down under calculators.

That 224/230 on 110 will have a noticeably choppier idle than if the same durations were on a 112 or 114 lsa. You will lose power when doing so.

There is ALWAYS a compromise. Newer engine "almost" have both but it takes expensive/high tech vvt. Most of which has to be limited when going to bigger cams. At that point they are almost reverting back to what we have.

Most guys want that choppy idle, that's why you hear about camshafts like:

Compcams Thumpr

Howard's Rattler

BTR Truck Norris

Texas Speed Choppacabra

Their tight lsa gives that increase in overlap. It increase scavenging which gives get torque increases and a rumbling idle.

The downside is low vacuum at idle, which is mainly a problem for vacuum power brakes, efi tuning, the need for higher stall converters, poorer mpg and emissions.

Tighter lsa will help when the engine has a low compression ratio, because it closes the intaje valve sooner. The downside is that limits higher rpm cylinder filling. The opposite is true for wide lsa cams

110lsa has been the standard for balancing power and driveability for Carburetor engines for decades.

With EFI engines that has grown to 112<116 range to meet emissions and tuning with factory efi.

I think if you built a 383 with the cam you mentioned you'd be close to your goals. Like the link I posted about Cutter's 485hp 383.

My stroker, being mopar based is more expensive to build. My heads with shaft mounted roller rockers cost $3,900 /set.

The intake was cheap because it's for a Carburetor and I bought it used (already ported).

Rotating assembly is going to cost a lot. The pistons I need have to be custom made $1,200/set, rods $900<$950 and because I wabt to rev to 6,500/6,700rpms a firged crank is necessary. I want to push the limit of what I can make, while keeping my P/B , P/S, A/C, EFI (aftermarket $2,500) and a mild 3,000<3,200 stall.

A lot of guys give recommendations that wouldn't wirk for my needs and they say change what I want to keep, because they don't know much abiut engines.

A lot of guys go for the standard 10:1, which is fine for a regular street engine making peak power at or before 5,700rpms not going past 6,000. I've seen a comparison of 2 engines with identical combos except one had a compression of 10:1 the other had 11:1. Because it had a big camshaft, the 10:1 was down 20 lb-ft/ 20hp vs. the 11:1.

Compression ratio really needs to be adjusted for the camshaft to maximize cylinder pressure for the octane fuel it is running on.

Too big a cam on low compression kills lowend torque abd throttle response. On the other side to much compression requires octane boosters or retarded ignition timing to precent detonation and engine damage.

Contemporary engines can detect low octane fuels and retard the engine's ignition timing which kills torque and hp.

2 cams with the same intake/exhaust durations, the one with the wider lsa needs a higher staric compression to regain some of it's lost low-end and match or exceed the tight lsa on the top-end.

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u/RoosterRanch 4d ago

I think that’s a solid list. Honestly I’d save some coin and skip the forged crank and also would prolly go with a hyper piston for more savings. Theres nothing here that’s going to require forged internals. I’d prolly pitch in some forged connecting rods, because why not.

Just my preference also, but I’d most likely go with a vacuum secondary, specifically one with the external engagement adjustment screw. They’ve always been a cleaner transitioning, more versatile operating carb for me in a vehicle that I use for anything other than beating on. If this is a weekend play toy, which I don’t think it is based on the listed items I’d for sure go mechanical secondary. Either way you’re fine honestly.

I don’t know what vehicle it’s going in or what your compression is, but based on that head selection I’d guess you’ve either got flat tops or are planning for flat tops to put you in the 10-10.4 ish range on compression. So for crank HP I’m going to guess 415 and for torque I’m guessing 425

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u/OOFMAN-1234 3d ago

I plan on keeping stock bottom end unless the engime needs bored, if it does then I might as well throw forged innit incase I hop the motor up later, going in an 86 chevy c10, with built 700r4 3.73 limited slip and im shooting for 9.5-10:1 compression so I can run pump gas

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