TSP Level 2A-R Prototype Specs and testing (Larry's motor)

if i was careful could i pull the heads and port them and smooth everything out without having to redo the valve job?im hoping to get the cars weight down to around 3600 with me in it 170lbs
i wish i would have ported the heads before i sent them to the machine shop but i was 17 then and didnt think about it.

 

i was thinking just gasket matching sides and top and polishing everything. ive heard cutting on the bottom does nothing.is that a bad idea? or you think i would hit a valve seat?

 

Lonnie, some chamber work is ok if you have a junk pair of valves you can insert while you do the work to protect the seats.

You really can't do a good job of port matching since you can't look down into the ports from the plenum to see how they align between the intake & heads. Using the gasket as a guide to modify the intake in one step and then the heads in another step won't do a thing for you because you can't see what the actual port alignment really is when they're bolted together.

It can be done with dye and composition intake gaskets, or if you have a borescope handy. In the end, size-wise all head ports must be equal to or greater than the intake so that the air/fuel mix doesn't see a "bump" on its way down.

Unfortunately, most homespun matching jobs have the intake/head port interfaces looking like the bell ends of two trumpets stuck together.

Devon

P.S. Might be a good idea to start your own thread on this one so we don't keep polluting the original topic...

 

i didnt plan on dragging it on. it was just a simple question anyways. i can just do a search on it

 

I have Jim working a 470 short block as we speak with a roller version of the 290H. It will eventually have TA stage 2 SE heads with an SPX intake. This is going to be used for auto cross in a 1970 GXS clone with a RS600 trans and moser 12 bolt sporting 4:11 gears. Hoping for 600+ HP.

 

What happened to the Quadra-Jet? Larry without a Q-Jet? Ahhh yess, starting to remember his testing on that now... Would be interesting to see how much would be lost going back to the Q-Jet. It seeing if you can run what Gessler runs, if that is even considered in practical terms to be Q-Jet anymore.

 

On his existing motor the Q jet was within 0.081 seconds and 1.33 mph in the quarter mile versus a 1000 cfm carb. This says to me there is no practical difference in performance on the street while the Q jet is much friendlier.

 

Music to my ears. I've never been a Holley fan though ironically right now I have them on everything.

 

Larry,

It would be interesting, but my past data indicates that the stock configured 800 cfm Q-jet will be too small at this HP level.

Look at this motor I built for a board member last year.

With an 800 Q-jet:



And with the 1000 HP



A couple things to look at here..

Manifold pressure - (Vacuum)- Any number above 1.0 at WOT is an indication that the carb is the limit to airflow, and the Q-jet is creeping up on the vacuum reading past 5000 rpm.

This causes the Total airflow thru the engine to be reduced, compare the air number between the two.

This airflow restriction is going to be even more pronounced with your motor, as your flowing even more air, making more power.




I believe Cliff has a modification that he does to Q-jets at this level, which involves removing the primary booster ring, eliminating that restriction to airflow.

I will email him and get his input on this.

JW

 

I'm certainly more than impressed with the 800 Q-Jet that Cliff did for me. My motor is well within the 800cfm limits course, but I'll never bother with having anyone else rebuild one for me. I had a Holley 750 on my '71 (400CI), and it ran good, but it was out-of-the-box new with my tuning (which isn't all that great). So, I have nothing against Holley.

But, why not go with dual Q-Jets, Larry? :Brow: Wasn't there a good thread on dual fours from Jim this past year?

 

LOL. I guess I didn't realize there isn't a single plane intake for dual quads. Tells you how much I know. ou: It's amazing how far a single 800 Q-Jet will get you, though.

Well, I'm just gonna stay tuned and try to learn something new again.

 

Could always modify a nailhead intake to fit. T/A sells some cool dual and tri carb setups for them old school motors.

 

Larry,

No, I have never had any customer complain of issues like your describing.

I have always used the 08513-1 1000 HP from Holley.

 

I never had any problems like that with my AED 950.