lowering blocks - The 1947 - Present Chevrolet & GMC Truck Message Board Network

panhead59 · 07-31-2017, 08:59 AM

I;m getting ready to do a 4/6 lowering job on a 68 swb. I've read that it would be best to use the longest REAR spring (4" drop) and a 2" block to give me the desired 6" total drop in rear. But then I've read that 1 1/2" blocks are about the max if I wanted to use 15" wheels. Can anyone confirm this ? I really don't want to use huge wheels, I'd rather have the "old" look as far as wheels are concerned. Just 15" Cragars are what I have in mind. Maybe I just need to look more closely at different wheel sizes (pics) and compromise. Whadaya think I should do? Just go with the 6" drop springs and not worry about the wheel size?

**hewittca** · 07-31-2017, 11:01 AM

The concern with using drop blocks and smaller diameter wheels is the scrub line. As in, if the tire were to essentially come off the rim, what would touch the ground first? You want it to be the rim and not any fixed part of your suspension. With smaller diameter wheels, you run the risk of the u-bolts being the first point of contact with the ground, not your rim. That would be a rough ride! What you can do is measure your current u-bolt to ground and rim to ground distances. Whatever the difference is between those two (where your u-bolt to ground should be the larger of the two), that is the absolute maximum block height you could use. If it's less than two inches, you definitely don't want to use 2" blocks. All that said, I think there are quite a few guys running 2" blocks on 15" rims, so you should be ok. It is good to check though.

panhead59 · 07-31-2017, 05:28 PM

Thank you sir.

**PGSigns** · 07-31-2017, 08:21 PM

Blocks also move the rear ahead a bit so keep that in mind. You will want to look at the pinion angle. I have three degrees milled off the top of my blocks. They started life about 1 1/4" tall before I cut them. I have 5" springs and the blocks.
Jimmy

panhead59 · 08-02-2017, 08:47 AM

Whats wrong with just using the 6" drop springs ? Sounds like less "hassle", less problems. Plus I can get everything in a kit that way. I see no blocks in any complete kit, so going that route means buying everything separate. It's just a tad worse ride? Or a REALLY noticable difference? I mean- it's a truck!!!! I ain't really worried about being comfortable.

**hewittca** · 08-02-2017, 09:36 AM

I don't have any experience with the 6" springs versus 4" springs and blocks, so I can't comment there. The general consensus is just that the 4" springs plus blocks setup gives you more spring travel and should be a better ride, but the better ride part is subjective. For me, I have a different reason for using 4" springs and blocks over 6" springs. That is, I still use my truck as a truck and need the extra travel for when it's loaded up. Plus, you can get 4" drop HD springs, whereas the 6" springs are just a smaller wire diameter spring not really meant for heavy loads.

SCOTI · 08-02-2017, 11:32 AM

Quote:

Originally Posted by hewittca

I don't have any experience with the 6" springs versus 4" springs and blocks, so I can't comment there. The general consensus is just that the 4" springs plus blocks setup gives you more spring travel and should be a better ride, but the better ride part is subjective. For me, I have a different reason for using 4" springs and blocks over 6" springs. That is, I still use my truck as a truck and need the extra travel for when it's loaded up. Plus, you can get 4" drop HD springs, whereas the 6" springs are just a smaller wire diameter spring not really meant for heavy loads.

The best ride will come from the correct shock & the longest shock stroke possible.

Budget approach 4" springs & 2" blocks vs just 6" springs yields longer shock travel thus a better ride.

panhead59 · 08-02-2017, 05:26 PM

What's the "non budget" approach? Air bags? Truck will have new wood bed, so no hauling. Just a Sunday toy.

SCOTI · 08-02-2017, 05:30 PM

Quote:

Originally Posted by panhead59

What's the "non budget" approach? Air bags? Truck will have new wood bed, so no hauling. Just a Sunday toy.

I would do bags if it's still going to be used as a truck. Springs & blocks otherwise.

panhead59 · 08-06-2017, 10:00 AM

OK tks guys. Now how do I buy these blocks? CCP and ece websites say they make em but can't seem to find them on there website. How to order and where?

BossHogg69 · 08-06-2017, 11:42 AM

supporting vendors:
http://67-72chevytrucks.com/vboard/s...454824&page=18

https://www.performanceonline.com/60...rear-aluminum/

http://www.brotherstrucks.com/63-72-...tinfo/LBU6372/

CPP:
http://www.classicperform.com/Store/2016/CP39028.htm

You could probably call ECE and see if they have them if they aren't on the website...

07-31-2017, 08:59 AM	#1
panhead59 Registered User Join Date: Feb 2012 Location: Vinton, Va. Posts: 473	lowering blocks I;m getting ready to do a 4/6 lowering job on a 68 swb. I've read that it would be best to use the longest REAR spring (4" drop) and a 2" block to give me the desired 6" total drop in rear. But then I've read that 1 1/2" blocks are about the max if I wanted to use 15" wheels. Can anyone confirm this ? I really don't want to use huge wheels, I'd rather have the "old" look as far as wheels are concerned. Just 15" Cragars are what I have in mind. Maybe I just need to look more closely at different wheel sizes (pics) and compromise. Whadaya think I should do? Just go with the 6" drop springs and not worry about the wheel size?

07-31-2017, 11:01 AM	#2
hewittca Senior Member Join Date: Jun 2014 Location: Mocksville, NC Posts: 1,723	Re: lowering blocks The concern with using drop blocks and smaller diameter wheels is the scrub line. As in, if the tire were to essentially come off the rim, what would touch the ground first? You want it to be the rim and not any fixed part of your suspension. With smaller diameter wheels, you run the risk of the u-bolts being the first point of contact with the ground, not your rim. That would be a rough ride! What you can do is measure your current u-bolt to ground and rim to ground distances. Whatever the difference is between those two (where your u-bolt to ground should be the larger of the two), that is the absolute maximum block height you could use. If it's less than two inches, you definitely don't want to use 2" blocks. All that said, I think there are quite a few guys running 2" blocks on 15" rims, so you should be ok. It is good to check though. __________________ Builds: Green Gus the 68 C10 ; Sullii the 72 1500 - Instagram: @dr.hewitt - C10 Concept/Development Photos: Master Thread

07-31-2017, 05:28 PM	#3
panhead59 Registered User Join Date: Feb 2012 Location: Vinton, Va. Posts: 473	Re: lowering blocks Thank you sir.

07-31-2017, 08:21 PM	#4
PGSigns Senior Member Join Date: Jan 2011 Location: Hayes Va Posts: 4,569	Re: lowering blocks Blocks also move the rear ahead a bit so keep that in mind. You will want to look at the pinion angle. I have three degrees milled off the top of my blocks. They started life about 1 1/4" tall before I cut them. I have 5" springs and the blocks. Jimmy __________________ 60 to 66 Chevy and GMC window decals http://67-72chevytrucks.com/vboard/s...d.php?t=661131 Good friends, good food and a hotrod what else do you need? 1966 BBW long fleet Daily driver 1965 BBW short fleet Sold and going to a good home 1965 Suburban 2003 3500 Duramax 2005 Ultra Classic

08-02-2017, 08:47 AM	#5
panhead59 Registered User Join Date: Feb 2012 Location: Vinton, Va. Posts: 473	Re: lowering blocks Whats wrong with just using the 6" drop springs ? Sounds like less "hassle", less problems. Plus I can get everything in a kit that way. I see no blocks in any complete kit, so going that route means buying everything separate. It's just a tad worse ride? Or a REALLY noticable difference? I mean- it's a truck!!!! I ain't really worried about being comfortable. Last edited by panhead59; 08-02-2017 at 08:52 AM.

08-02-2017, 09:36 AM	#6
hewittca Senior Member Join Date: Jun 2014 Location: Mocksville, NC Posts: 1,723	Re: lowering blocks I don't have any experience with the 6" springs versus 4" springs and blocks, so I can't comment there. The general consensus is just that the 4" springs plus blocks setup gives you more spring travel and should be a better ride, but the better ride part is subjective. For me, I have a different reason for using 4" springs and blocks over 6" springs. That is, I still use my truck as a truck and need the extra travel for when it's loaded up. Plus, you can get 4" drop HD springs, whereas the 6" springs are just a smaller wire diameter spring not really meant for heavy loads. __________________ Builds: Green Gus the 68 C10 ; Sullii the 72 1500 - Instagram: @dr.hewitt - C10 Concept/Development Photos: Master Thread

08-02-2017, 05:26 PM	#8
panhead59 Registered User Join Date: Feb 2012 Location: Vinton, Va. Posts: 473	Re: lowering blocks What's the "non budget" approach? Air bags? Truck will have new wood bed, so no hauling. Just a Sunday toy.

08-06-2017, 10:00 AM	#10
panhead59 Registered User Join Date: Feb 2012 Location: Vinton, Va. Posts: 473	Re: lowering blocks OK tks guys. Now how do I buy these blocks? CCP and ece websites say they make em but can't seem to find them on there website. How to order and where? Last edited by panhead59; 08-06-2017 at 11:01 AM.

08-06-2017, 11:42 AM	#11
BossHogg69 motor exploder Join Date: Mar 2009 Location: Pittsburgh, PA Posts: 2,346	Re: lowering blocks supporting vendors: http://67-72chevytrucks.com/vboard/s...454824&page=18 https://www.performanceonline.com/60...rear-aluminum/ http://www.brotherstrucks.com/63-72-...tinfo/LBU6372/ CPP: http://www.classicperform.com/Store/2016/CP39028.htm You could probably call ECE and see if they have them if they aren't on the website... __________________ Adam 1969 Chevy CST/10 stepside, DART Big M/TREMEC Magnum Extreme/3.73's w/Detroit Truetrac 1965 Chevy Bel Air Wagon (daily driver), 327/TH350,10 bolt w/3.08's 1961 Chevy Bel Air Sport Coupe, ZZ454/M21/9" rear w/3.50's & Detroit Truetrac 2005 GMC 1500 ccsb 2wd, 6.0L/4L65e/3.73 G80 2006 GMC 2500HD ccsb 4x4, DMax LBZ/Allison 6spd/4.56's w/Detroit TrueTrac Use the SEARCH function on this forum - it is your friend!!

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