cam selection

[dylan]

I'm looking for some insight on selecting a cam for my stock 1991 gen V 454 engine. The engine is in a truck and I'm looking for a torque monster. The engine pretty much never sees over 4,000 RPM's. My main issue with it, is the lack of ability to hold 5th gear at highway speeds. I run around 2100-2400 rpms on the interstate and the truck just struggles to hold 5th hauling any weight, or climbing slight inclines even empty. Its pretty much a stock TBI unit. Has a chipped ECU from TBIchips.com, full length headers down to true dual 2.5 inch exhaust. I have done some research on this site about this engine, so I know it lacks power due largely to a low compression ratio(especially for my area around 4000' and up). Once the motor starts to get tired, I plan on doing a slight build. Bumping the compression up, porting the heads some, and swapping over to a carb. For now, I want to just throw a cam in it that will work for what I use the truck for. I was looking into these units here:

https://www.summitracing.com/parts/cca-cl11-203-3/overview/make/chevrolet
https://www.summitracing.com/parts/cca-cl11-205-3/overview/make/chevrolet

http://garage.grumpysperformance.com/index.php?threads/port-speeds-and-area.333/

I'm more of a diesel performance guy, so gas engine performance is new to me. Will one of these cams work good for what I do? is there a better option out there? Will these work with the nonadjustable valve terrain that this engine has?

 

[Strictly Attitude]

Neither one of those cams are ecu friendly so you would need a new tune with a cam change. would a new cam help yes but if it was me I would do an intake and a carb or holly stealth unit first.

 

[dylan]

ok. so say I do those things first, than the cam. Would either of the cams work with the nonadjustable valve terrain that these peanut port heads have?

 

[Grumpy]

the answer to your basic question on how to maximize the bbc engine torque is almost totally dependent on your available cash your willing to use too obtain the goal you set.
if your goal is brutal low and mid rpm torque its certainly available but it won,t be cheap or easy to do without some research.
I could suggest a cam change but it won,t result in a huge power increase, Ive built dozens of similar engines and a simple cam up-grades not going to produce what your looking to achieve!
yes you can get to something like 550 hp and 600 ft lbs , with a properly built and rather streetable BBC, if you want to build a mild 496 stroker,
You can go the N/A route, with a 4.25" stroker crank, high compression pistons and a roller cam and smaller combustion chamber aluminum cylinder heads, and yes the better flowing smaller combustion chamber heads and the stroker crank assemble to build a kick-butt 496 is a common route, but thats both expensive and it requires a total engine rebuild.
your engines low compression is a huge problem, that a simple cam change alone will more than likely NOT over come, your lack of power,by resulting in a huge increase in torque.
yes a upgrade to an adjustable valve train, a roller cam would help, but torque is basically dependent on effective displacement and compression.
your budget will limit the results,but you certainly have several options,
(a very effective way to boost torque on an engine like that, and what I would suggest here) would be to install a centrifugal super charger , that route is much easier,, you could rather easily boost rear wheel output by well in excess of 200 plus ft lbs
on a 454 low compression engine, and if you went the lower compresion 496 stroker route with better flowing herads even greater potential gains are available.
https://www.procharger.com/automoti...eted/gm-carbureted-aftermarket-efi/sbbb-chevy

http://www.superchevy.com/how-to/48499-cheap-horsepower-engine-build/

http://www.superchevy.com/how-to/project-cars/sucp-0612-supercharged-496-motor/

https://www.powerblocktv.com/episode/HP2009-12/454-budget-build#.WBz_hPkrK9I

http://www.hotrod.com/articles/chevy-big-block-crate-engine-build-up/

http://www.speedwaymotors.com/Weian...gn=CSEGOOGLE&gclid=CJqRptmJkNACFUMDhgodi_ALDQ

http://garage.grumpysperformance.com/index.php?threads/chevy-big-block-vi.9857/

http://garage.grumpysperformance.co...le-that-don-t-use-resources.12125/#post-58374

http://garage.grumpysperformance.co...-on-the-cheap-well-to-start.11739/#post-55478

http://garage.grumpysperformance.co...-calculators-and-basic-math.10705/#post-46737

http://garage.grumpysperformance.co...-displacement-street-engine.10961/#post-48577

http://garage.grumpysperformance.co...k-for-in-a-good-engine-combo.9930/#post-46399

http://garage.grumpysperformance.co...ting-started-in-the-car-hobby.339/#post-21733

http://garage.grumpysperformance.co...ines-budgets-and-those-deals.6624/#post-20986

http://garage.grumpysperformance.com/index.php?threads/sources-of-bbc-info.752/#post-1075

http://garage.grumpysperformance.com/index.php?threads/matching-parts-and-a-logical-plan.7722/

http://garage.grumpysperformance.com/index.php?threads/another-496bbc.5123/

why not call the tech dept at all five cam manufacturers linked below, and get their input,
(without discussing or letting anyone at those individual tech departments,know you talked to other sources
.what any other cam manufacturer might have said in any way)
write down the cam specs they suggest, lift duration and lsa,

then average the results and
select the cam thats the closest match, to that average , of the 5 cams that were suggested.

crane (386)310-4875

crower 619.661.6477

erson 800-641-7920

lunati..662-892-1500

ISKY 323.770.0930

what your basically trying to do is to maximize operational compression,
over the useful rpm range
(this maximizes the torque curve efficiency,)
but, while keeping that cylinder pressure under the detonation threshold

most cam manufacturers will want some basic info similar to this crower cams info request sheet.

related info
http://garage.grumpysperformance.com/index.php?threads/semi-fool-proof-cam-sellection.82/

http://garage.grumpysperformance.com/index.php?threads/how-to-read-a-cam-spec-card.1477/

http://garage.grumpysperformance.com/index.php?threads/the-mechanics-of-adv-ret-a-camshaft.4532/

http://garage.grumpysperformance.co...d-high-spring-pressures-don-t-work-well.1489/

http://garage.grumpysperformance.com/index.php?threads/valve-train-clearances-and-problems.528/

http://garage.grumpysperformance.co...e-springs-and-setting-up-the-valve-train.181/

http://garage.grumpysperformance.co...-the-charts-calculators-and-basic-math.10705/

http://garage.grumpysperformance.co...lsa-effects-your-compression-torque-dcr.1070/

 

[dylan]

thanks for all of the links! I have a lot of reading to catch up on. The procharger route is out. I could have fairly decent rebuilt engine for the price of that thing. I should have said in my original post. I guess I'm not looking for a giant jump in power. I'm mostly looking for a little extra kick down low to help it maintain 5th on the highway. If I had to put a number on it, maybe 20 ft lbs or so.