Projected engine build up........... - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans Advertise
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 05-29-2007, 12:32 PM
Registered User
 
Join Date: Apr 2007
Location: Central NY
Age: 45
Posts: 143
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Projected engine build up...........

I am hoping to but some money into my 82 T/A, primarily into the engine. It has a 010 block 350 from 1974 (prolly a 2 bolt main) that is hooked up to a 1978 aluminum Super T 10 trans (2.64 1st gear, I think). I want to perform a cam, valvetrain, heads, and header swap. I want to build it to make huge low to mid range torque and maximum HP in the 4500 - 5000 RPM range. Parts I'm thinking about are:

World products Sportsman II heads with 64cc chamber and 200cc runners (angled plug) with 2.02/1.60 valves, 5/16 guide plates, 1.250 hi-po springs and multi angle valve job (rated for a .550 lift)

Rhoades hydraulic lifters (the ones that shorten duration and lift at low RPM for increased low end torque and vacuum)

Full roller rocker arms (1.52 ratio)

Either a Comp Cams 268H or 270H cam (268 is 218 duration at .050 with a .454 gross lift, 270 is 224 duration at .050 with a .470 gross lift. Both cams are 110 lobe angle)

Ebelbrock 1 5/8 street legal header kit

Will use these with a Holley street dominator hi rise intake with a Carter 650 AFB carb. Aiming to have 9.5 compression, no more than 10.1 (will run 93 octane gas)

Can anyone tell me if this is going to be a good combo and what power numbers I could expect to have? I have never done a buildup like this before, and I can use all the help I can get, lmao.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 05-29-2007, 12:38 PM
Member
 
Join Date: Jan 2005
Location:
Posts: 3,700
Wiki Edits: 0

Thanks: 0
Thanked 4 Times in 4 Posts
I think a 170-180cc heads would probably provide more usable street torque but I may be wrong. Pick the cam that'll give you a dynamic compression ratio closest to 8-1 for use with premium.
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 05-29-2007, 03:36 PM
Member
 
Join Date: Dec 2004
Location: San Antonio, Texas
Age: 56
Posts: 4,018
Wiki Edits: 0

Thanks: 0
Thanked 26 Times in 26 Posts
The cams you are considering make peak power well above 5000 rpm.

A 268 makes peak power around 5700 rpm and a 270H makes peak power a around 6000 rpm.

For peak power at 5000 rpm consider using a 252H. This cam would work nice with a 2.73, 3.08, or 3.23 gear. What gear are you using??

A 260H also makes good torque but peak power would be over your target range. Will work nicely with a 3.23 to 3.55 gear and not too badly with a 3.08 and a 4 spd.

I would not go over 9.25:1 cr with and engine designed to make peak power at 5000 rpms unless alum. head were used.

Your intake is not designed for a 5000 rpm peak power engine. Consider using a performer intake.

200cc head is also to big for your power goals. A set of vortecs or some 170cc edelbrocks performer heads would be much better.

Use regular lifters. Rhodes lifters make a lot of noise and are not intended for long drives. Again, peak power at 5000 rpm doesn't fit the need for rhodes lifers.

With Performer heads and intake, 9.5:1 cr, and a Compcam 252H, your engine could make 325 to 340 hp at 5000 rpm and 375 to 400ftlb of torque at 3000 rpm. Get good mpg, idle smooth, and pull 18 to 19 inhg on vacuum.
Reply With Quote Quick reply to this message
 
  #4 (permalink)  
Old 05-29-2007, 04:27 PM
Registered User
 
Join Date: Apr 2007
Location: Central NY
Age: 45
Posts: 143
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I would like to make about 400 horses and 400+ lb/ft of torque. I guess I could go for a cam that makes power higher up in the RPM range, but I am unsure of how well the bottom end is. The car has 45-50 lbs of oil press. at idle. I have hat this engine up to 6,000 RPM a time or two, but it worries me to rev it like that. BTW, it has 3.23 gears and posi in a stock GM 7.5" rear. I think the motor is making big power already (prolly around 340 horse and maybe 360 lb/ft torque) I mean, it pulls like a monster. I burned rubber last week with it, musta smoked em for about 75-80 feet or better (had to stop at the stop sign, tires were still spinning.. )

All in all, I want to be able to drive it on the street, and sometimes I'd like to take it to the local 1/8th mile for some legal fun. What can I do to make this engine fit my goals?
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 05-29-2007, 04:53 PM
Member
 
Join Date: Dec 2004
Location: San Antonio, Texas
Age: 56
Posts: 4,018
Wiki Edits: 0

Thanks: 0
Thanked 26 Times in 26 Posts
You think you have 340 hp already? If you are using a stock cam and stock heads then the most you could be making is around 250-260 hp with headers. Could be 280hp with some head work but that is about it.

The 260H or 268H would be a good choice considering the 4 spd, 3.23 gears, and your desire to make more hp. And could make around 375hp/400ftlb with a good set of heads and enough compression. A 270H would start losing low rpm torque and would require steeper gears to run right (3.55's).

As you already know, torque is fun on the street. Don't mess it up with too much camshaft and too much cylinder head. Don't worry about the hp number so much. And don't worry, I'm sure your engine will make it to 6K rpm without any problems.

Do you already own the set of sportsman II's?

What carb are you using now?

Have you ever ran your car down the 1/4 mile? If so, what was your trap speed?

Maybe a little 150hp shot of n20 for the 1/8 track will be enough to make you happy.
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 05-29-2007, 05:04 PM
RippinRon's Avatar
Member
 
Join Date: Jun 2004
Location: Thornbury, Ontario
Age: 39
Posts: 948
Wiki Edits: 0

Thanks: 0
Thanked 1 Time in 1 Post
Are you sure your headers will work with angle plug heads?
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 05-29-2007, 08:40 PM
Registered User
 
Join Date: Apr 2007
Location: Central NY
Age: 45
Posts: 143
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
I haven't run the car on the quarter yet, but if I had to guess, it'd prolly be around 12.75 to 13.0 (can't hook up). I am running the motor right now with a Holley street dominator hi rise and a 650 Carter AFB carb. Heads are GM, but I think they are small chamber, but I never had them off. The car has a crazy compression ratio (killed 4 stock starters, each only lasted 1-2 mos NEW... ) It will ping on anything but 93 octane. The cam has a slight lope, and I can feel the engine "kick in" around 2000 RPM. Then it morphs into a monster, lol. It has too much torque for the stock torque arm, I've broken the mount a few times, and have bent the torque arm totally out of shape once. However, it has the log manifolds and a.i.r. pump hooked up. I still think it is making pretty good power despite that, but there is always room for more.......

I have a theory about the car. Word has it that it was owned by a dirt modified racer who bought the car minus motor and tranny. After the race season ended, he retired the short block and tranny to the Trans Am, put a stock intake and valve covers on it, and beat the hell outta the car. Got tired of fixing broken driveline parts and sold it to a local lot, where I bought it. The guy that owned the lot told me "You're gonna kill yourself in that thing....." I beleive a lot of that story, because the car overpowers the driveline for sure.

Last edited by Trans Am Tony; 05-29-2007 at 08:47 PM.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 05-30-2007, 07:00 AM
Member
 
Join Date: Dec 2004
Location: San Antonio, Texas
Age: 56
Posts: 4,018
Wiki Edits: 0

Thanks: 0
Thanked 26 Times in 26 Posts
So, why mess with it? Runs good, leave it alone.
However, headers would help a lot but get ready for a noisy cab.

If you ever get to run it down the 1/4 mile track then use this formula to estimate rwhp.

HP= ((et trap speed/234)**3) x (car weight + driver)

So if you run 100mph and your car weighs 3400lbs and you weigh 200 then....

hp = ((100/234)**3) x (3400 + 200)
hp = ((0.4273)**3) x (3600)
hp = (0.078046 x 3600)
hp = 281 rwhp or 1.2 x 281 (337 crank hp)
Reply With Quote Quick reply to this message
  #9 (permalink)  
Old 05-30-2007, 09:49 PM
 
Last wiki edit: Computer dyno simulation and engine building softw...
Join Date: Nov 2001
Posts: 91
Wiki Edits: 3

Thanks: 0
Thanked 0 Times in 0 Posts
Here is the simulation. Also, if your T/A is geared like the one I had years ago, your rear end ratio is low. I think mine was something like 2.73:1, I wouldn't get out of 2nd gear in the 1/4 mile at 90mph trap speed. A gear change in that case would have made wonders. I do miss that car though, someday I hope to get another one.

Quote:
Originally Posted by Trans Am Tony
Can anyone tell me if this is going to be a good combo and what power numbers I could expect to have?


Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:
Insurance
Please select your insurance company (Optional)

Log-in



Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Build for Hp or Torque? Venturat Engine 76 09-23-2008 10:22 AM
Build me an engine! (on paper) :p mgray10 Engine 5 02-29-2004 04:02 PM
engine build camnova Engine 1 02-15-2004 05:50 PM
first engine build 71chevellepa Engine 1 09-13-2003 04:30 PM
Engine build for hire,decision 78 monte Hotrodders' Lounge 9 05-10-2003 09:44 PM


All times are GMT -6. The time now is 09:50 PM.


Powered by vBulletin® Version 3.8.8
Copyright ©2000 - 2020, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2020 DragonByte Technologies Ltd.
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.