Thread: H/C/I/carb on 4 bolt 350

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Hi guys! New to the forums, not new to Chevys but new to the sbc. I had an LS1 Camaro and then an LS2 GTO before I went to the dark side and had a couple fox bodies. Now I'm back on the bow tie scene with an 87 MC SS. It has a factory rebuilt 4 bolt 350 in it, converted to carb, pretty healthy, but bone stock. It's mated to a rebuilt 700R4 (yes I have paperwork for both) I'm looking to make a few more ponies without adding a blower or nitrous. 400 would be nice, but maybe that's aiming a little high. This car will be a street/strip car with the emphasis on street. I'm not worried about gas mileage or passing smog, just want something that idles nicely, sounds mean and goes like hell through the entire powerband (or at least most of it)
Now, like I said I'm not too familiar with these engines, so at the moment I'm debating between doing a new high comp rebuild, or throwing a small blower on it, or just doing heads, cams, intake & carb, but leaning more toward the latter option unless you guys suggest something else. If I just do H/C/I & carb my budget is about 3k, but I suppose I can stretch it out if necessary. Obviously the budget gets bigger if I do one of the first two options, but that's a big reason I'm leaning toward the last option; don't really intend to go broke on this thing.
So my question; what is the best street/strip H/C/I/carb combo I can put together on this thing so I no longer feel like I'm riding around in granny's chevy?

Welcome to CHR!

We have a couple Monte Carlo fans here including our favorite hot rod lady Barb aka “Junkyardgirl”. Lots of good folks here and we hope you have a long and happy stay with us!

The 1987 Monte Carlo came with an LM1 350. It was the base 5.7 L (350 cu in) with a 4-barrel carburetor (usually with a QuadraJet) used in all Chevy passenger cars until 1988. It was rated at a whopping 180 horsepower and all (in the Monte Carlo) were mated to 4 speed automatic transmissions. Weigh in stock form is about 3400 pounds.

It’s easy to get 400 horsepower out of a 350 in your $3K budget with any number of head/cam/intake/carb combinations; however, the limiting factor in your current drive train will be the stock 700R4 as it is good for about 350 lb/ft. If you put 400 plus in front of a stock transmission and habitually shift at WOT it will fail. The good news is that a mild build on the 700R4 will allow it to handle 450 lb/ft and 450 plus horsepower – see Bowtie Overdrives - View Item. While I know you have a new rebuild transmission, unless it was built by a reputable high performance shop you may be better off to eBay it and recover a few dollars toward a quality HP unit and a good 24-2600RPM converter.

The engine can easily produce 400 plus. A set of AFR Street 180 Cylinder Heads should give you about 9.5:1 on an LM1 base engine with the stock .051 thick gasket (assuming stock deck height of 9.025 – if it’s been squared you’ll need to do some math). A hydraulic cam in the 224/224 @ .050 lift range with .470/.470 lift would work well with these heads. Assumption is that your 1987 is a roller block (transition year - most are, some are not) – if not I’d recommend a roller cam and a 1987 block should already be ready for it. I’m a bit leery of flat tappet cams unless the installation and break-in is done exactly by-the-book.

Top the engine with an Edelbrock 7101 Performer RPM and a 750 cfm Holley with vacuum secondaries and a good set of 1-5/8” headers and you should see 400 horsepower. Assumption is that you have a stock HEI distributor – if not get one. Start with 8-10 degrees at initial and 34 degrees all in.

Have fun and let us know what you decide to do.

Again, Welcome to CHR!
Glenn

Awesome, thank you Glenn!
By the way I should specify, though I assume you guys have probably made the connection; I'm looking for 400 at the crank, which I believe would put me around 330 at the wheels (correct me if I'm wrong) while keeping it as streetable as possible. Nothing too anemic at lower RPMs. 350 rwhp is the real goal, but 330 should suffice, if it means a noticeable increase in driveability.
Basically I want to be able to hang with the H/C/I fox bodies around town.
On the 5.0 efi's pistons had to be notched to fit AFR heads. I'm guessing that's not the case for the sbc?
Also I was taught that Chevys typically like edelbrock carbs, whereas fords like holleys. Now that could very well be a bit of misinformation so if so then feel free to set me straight.
Also, that CR seems a little low. Would I be benefitted much by swapping in some higher comp pistons?

As for the tranny, it was a rebuild to oem spec so it will not handle the torque I'm hoping to make. Anyway, no problem I have great tranny builder (built my T56 to handle 500 and I attempted to break it for 40k miles plus with no luck) so I will get a quote from him on a performance rebuild, and if it's not worth it I'll go the route of a new built tranny and sell my stocker on eBay as suggested. Stall converter is a good idea, I will add that to the shopping list.
Also, any other must do mods I should consider?

Thanks again for the feedback!

Welcome. I like Glenns’ recommendations but there are a couple things I’d like to add.

Since you have the paper work on the 350 (instead of the factory installed 305) and you’re not worried about smog I would also look at the exhaust. If it hasn’t already been done, I would add a double hump crossmember and a true dual exhaust with long tube headers (not shorties). Personally I like the “pypes” X pipe, not so much for any added HP but because of the way it nicely tucks the mufflers under the body.

If you can afford the down time with the car, I think I would hold off buying heads until you pull the ones that are on there and can get the measurements needed to check the compression ratio (how far down in the cylinder the piston is……make sure you take measurements from both sides…, dome volume etc). From there you can make the determination on the chamber volume you need to come up with decent compression.

Downstream from the engine and transmission I would also look at the rear end. The Monte Carlos including the SSs only came with the 7.5 10 bolt. The better 8.5 were only on the T Type G Bodies, the GNX and the Olds H/O and 442 G Bodies. The 7.5 10 bolts are tougher than a lot of people give them credit for, but they still will only handle a certain level of abuse. Here is some reading on the rear end options you might find interesting.

Rearend Swap Tech

Anyway, there’s my 2 cents and again welcome.


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Not a problem, I actually pulled my strange 9 inch rear end from my last fox body and swapped the factory 8.8 in before I sold it. It's been sitting in my garage waiting to be sold, but how hard would that be to swap in?

It may be pretty simple if the 9" is set up to be a direct replacement for the 8.8. The 8.8 are becoming a pretty popular swap and as I recall all that is required is to relocate the spring cups from the G body axle you're taking out and weld them to you're 9" and pick up a couple of conversion upper control arms from E Bay or another supplier.

Do a search on Google or check out gbodyforum.com for specifics.


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Moser and a couple other companies make a bolt in 9" housing for the G bodies.

Great! I have done some research on swapping my. 9" rear end in, and have ordered a Moser housing, so I should be able to get to work on that this weekend. Talked to my tranny guy, and looks like it will be more efficient to sell my tranny and order one of those bowtie level 2s.
Now here's what I'm thinking at the moment; I've seen both the AFR 180s and Patriot 185s (which If I'm not mistaken are just aluminum vortec castings) side by side and I can tell the difference in workmanship (the AFR ports are silky smooth, and the patriots pretty much look like vortecs) but I could save about $700 going with the Patriots. I will probably get a comp cams 12-211-2, edelbrock 7101 and a Holley 750, so as far as power, how big of a sacrifice really am I making if I opt for the patriots over the AFRs? If there's a better budget option please let me know, and if the AFRs are the end-all-be-all or are just in a conpletely different league than any other head option, I will spring for them.

And will I run into any problems getting the heads milled for slightly higher compression?

What are you looking for in terms of compression? I'd have to have a real specific reason for milling a new head - used ones sometimes need a touch to square the surface. For street cars with iron heads, try and stay below 10:1.

Originally Posted by glennsexton

For street cars with iron heads, try and stay below 10:1.

For iron heads I'd stay below 9:1 with todays ethanol blends, and not more than 10.5:1 with aluminum and you'll still probably be chasing premium fuel. What fuel are you wanting to run?

Actually ethanol has a higher octane rating - like 113 to 115 so it will support higher compression. My wife's daily driver is a Mustang GT 5.0 and it has 11:1 compression ratio and runs fine on the 10-15% ethanol we have in Oregon all year around. Granted it's aluminum, but i wouldn't worry about ethanol as a deal breaker in building a 9.5:1 versus a 10:1 iron headed engine.

10:1 cr would be great. I plan to run 91, though it's CA, so I know our 91 is not the greatest. 9.5:1 will suffice if it's better to leave well enough alone. I plan on buying my heads brand new. The Patriot 185s are looking really nice, having read this article Eight Budget Small Block Chevy Heads Tested - Car Craft Magazine All Pages

but I will pony up for the AFRs if they're a much better option. Is 450 at the crank a lofty goal? At the end of the day I'm more concerned with having a nice powerband than big numbers up top, but I'm thinking the cam should take care of that. I'm looking at a comp cams 12-211-2 but am open to suggestion.

Glenn, you really don’t get into the high octane rating (113 to 115) unless you’re talking about E85 and to really see much benefit from the E85 you need to start looking at CRs starting around 12:1. E10 premium still only ranges between 91- 94 octane depending on where you are.

Aluminum heads of better design, camshaft profiles and (probably most importantly) fuel injection and timing that are computer controlled allow the newer engines to run higher compression like we used to back in the “good old days”.

If MrGody lived at a higher altitude (say around 4500 ft) and the car was never going to leave that general area I might be tempted to go a ½ to ¾ point higher on the CR, but LA is about as close to sea level as you can get. On a carbureted engine with iron heads I tend to agree with Roger about a true 9:1 being about the maximum compression you’d want to run on pump gas.


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Originally Posted by rspears

For iron heads I'd stay below 9:1 with todays ethanol blends, and not more than 10.5:1 with aluminum and you'll still probably be chasing premium fuel. What fuel are you wanting to run?

Glenn, What I intended to type was "....not more than 9:1..." for iron heads, not "...below 9:1..." My apology.

Mike, thanks for your input and insight.