Engine Blueprinting - The 1947 - Present Chevrolet & GMC Truck Message Board Network

cfinance · 01-22-2008, 02:28 AM

I've torn apart my 350 in prep for a mild performance rebuild: >= 350 hp/ci, budget of $2500-$3000. What is the difference in the build tolerances between a "blueprinted" engine and a good, careful rebuild? Where would I get the needed tolerances for a blueprinted build? Is it worth the hassle and extra hours?

The truck is a mid-life project, not a daily driver. The main reason for the build is for the experience...and to show it off at the occasional stop light and burger joint.

I'm an apprentice machinist and know enough to get in trouble. Please help me get in trouble

71Dragtruck · 01-22-2008, 05:41 AM

This is my take on the subject and they way I've had it explained to me. You don't hear the term blueprinted very much anymore and even though it is in referance to exact factory specs, by today's standards a good rebuild is pretty much blueprinted. If you deck and square your block, line bore and torque plate hone it, measure all your clearances, resize your rod ends, cc your heads etc. making sure all is equal cylinder to cylinder, you've pretty much blueprinted your engine.

Like I've said this is my take of the word and some may take it more towards the ORIGINAL factory specs and measurements. As far as clearences go, that would depend alot on the intended use of the engine, and parts used.

bigjimzlll · 01-22-2008, 02:56 PM

The original factory specs(blue prints) aren't close enuff for a race engine. That being said, it is worth the time to check every measure ment and to correct any that are out.

Those carefully assembled engines always seem to run a little smoother and faster

cfinance · 01-27-2008, 04:55 PM

Thanks. Anyone know any good websites or links that provide a comprehensive checklist of machining applications with specs for a mild street race application?

Thanks again.

(Also, if this should be posted in Engine Drivetrain, sorry. Please let me know).

Myself · 01-31-2008, 04:38 AM

I've got a book on blueprinting, I can scan in the spec worksheets if you want.

*Billla* · 01-31-2008, 05:50 AM

The sole purpose of blueprinting is to allow easy replacement of assemblies - i.e. in a race engine ensuring that every single piston is exactly to spec, every rod and the combination. Where a race engine burns a piston, it makes it possible to replace that single rotating assembly without introducing variances in engine performance.

For example, I recently bought a set of SCAT I-beam rods. The lengths varied from 5.699 to 5.701...would you really want to resize the big ends of these rods to make them perfect? Thinks like indexing the crank stroke, etc...it's a lot of time and a lot of money.

IMHO this is expensive and useless for anything other than a purpose-built race only engine. Build to within spec and invest in a good balance - that's all that's needed.

01-22-2008, 02:28 AM	#1
cfinance Registered User Join Date: Aug 2006 Location: Port Orchard, WA Posts: 122	Engine Blueprinting I've torn apart my 350 in prep for a mild performance rebuild: >= 350 hp/ci, budget of $2500-$3000. What is the difference in the build tolerances between a "blueprinted" engine and a good, careful rebuild? Where would I get the needed tolerances for a blueprinted build? Is it worth the hassle and extra hours? The truck is a mid-life project, not a daily driver. The main reason for the build is for the experience...and to show it off at the occasional stop light and burger joint. I'm an apprentice machinist and know enough to get in trouble. Please help me get in trouble __________________ '71 C-10 Fleetside, 350/SM465 My truck is like my wife: they no longer look like they did on the showroom floor, but you just can't beat the beauty that comes with age.

01-22-2008, 05:41 AM	#2
71Dragtruck Registered User Join Date: Jun 2004 Location: Saskatchewan, Canada Posts: 1,368	Re: Engine Blueprinting This is my take on the subject and they way I've had it explained to me. You don't hear the term blueprinted very much anymore and even though it is in referance to exact factory specs, by today's standards a good rebuild is pretty much blueprinted. If you deck and square your block, line bore and torque plate hone it, measure all your clearances, resize your rod ends, cc your heads etc. making sure all is equal cylinder to cylinder, you've pretty much blueprinted your engine. Like I've said this is my take of the word and some may take it more towards the ORIGINAL factory specs and measurements. As far as clearences go, that would depend alot on the intended use of the engine, and parts used. __________________ Speed is just a matter of money, question is how fast can you afford to go? 8.95@148.97mph all motor haven't tried bottle yet Sponsored by: Getz Oilfield Consulting Hard Candy Customs Last edited by 71Dragtruck; 01-22-2008 at 05:43 AM.

01-22-2008, 02:56 PM	#3
bigjimzlll Senior Member Join Date: Dec 2001 Location: Redding,CA...USA Posts: 4,736	Re: Engine Blueprinting The original factory specs(blue prints) aren't close enuff for a race engine. That being said, it is worth the time to check every measure ment and to correct any that are out. Those carefully assembled engines always seem to run a little smoother and faster __________________ It's called "drag racing" if they called it "tic..tic..WHAM!..BANG! F*&K!!!", they'd have to keep the magazines under the counter with the other men's publications click the clicky to join the site.... http://67-72chevytrucks.com/vboard/payments.php 67 lwb..first hotrod in 25 years..540 best ET is 9.45 @ 141.44 Anderson,CA

01-27-2008, 04:55 PM	#4
cfinance Registered User Join Date: Aug 2006 Location: Port Orchard, WA Posts: 122	Re: Engine Blueprinting Thanks. Anyone know any good websites or links that provide a comprehensive checklist of machining applications with specs for a mild street race application? Thanks again. (Also, if this should be posted in Engine Drivetrain, sorry. Please let me know). __________________ '71 C-10 Fleetside, 350/SM465 My truck is like my wife: they no longer look like they did on the showroom floor, but you just can't beat the beauty that comes with age.

01-31-2008, 04:38 AM	#5
Myself Registered User Join Date: Oct 2005 Location: Northern Arkansas Posts: 1,142	Re: Engine Blueprinting I've got a book on blueprinting, I can scan in the spec worksheets if you want.

01-31-2008, 05:50 AM	#6
Billla Account Suspended Join Date: Sep 2005 Location: Monroe, WA Posts: 3,814	Re: Engine Blueprinting The sole purpose of blueprinting is to allow easy replacement of assemblies - i.e. in a race engine ensuring that every single piston is exactly to spec, every rod and the combination. Where a race engine burns a piston, it makes it possible to replace that single rotating assembly without introducing variances in engine performance. For example, I recently bought a set of SCAT I-beam rods. The lengths varied from 5.699 to 5.701...would you really want to resize the big ends of these rods to make them perfect? Thinks like indexing the crank stroke, etc...it's a lot of time and a lot of money. IMHO this is expensive and useless for anything other than a *purpose-built race only engine*. Build to within spec and invest in a good balance - that's all that's needed.



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